Become rich and famous, without doing anything more difficult than putting pen to paper! You only need start writing, and you'll soon be living a life of luxury, waited upon by servants as you travel the world! I didn't believe any of that, and besides, I already had my own maid. All I really wanted to do was write about what we did together, although I wasn't going to complain if I made a little pin money out of it. Nevertheless, it was exciting to think that modern technology meant that anyone, even I, could become a published author.
That was years ago, and I am no longer as naïve. Unfortunately, big companies don't always make things easy, especially when it comes to erotica - an area that, for all the talk of acceptance, is still mired in shame. Often dealing with massive corporations feels like taking on brainless beasts, with intractable systems causing preposterous problems. Discover some of the challenges of publishing erotic literature as I discuss battling behemoths.
If you wanted to read my first book, brassièred: a complete guide to brassière discipline, when it was published in January 2010, you had two choices - you could read it on the website, or you could buy it as a paperback from Lulu, the print-on-demand publisher that we're still using today. I assumed that would be enough to satisfy the two types of reader I envisaged for the book - those wanting to learn about brassière discipline for themselves, and those wanting to suggest it to someone else. I hadn't thought of writing stories back then, nor had I really considered the ways that people might want to read them if I did.
The paperbacks were printed from PDFs, put together by my technical wizard, and Lulu made it easy enough to sell these as well. With a little more work on my wizard's part, it was possible to wrap my words up as an another electronic format, EPUB, it needing only a box to be ticked for Lulu to sell these beyond their own store. By the end of 2012, you could buy everything that I had written as a paperback, a PDF or an EPUB from Lulu, or purchase the EPUB through Apple's iTunes or Barnes and Noble's Nook. We briefly flirted with allowing Lulu to sell some of the books on Amazon as well, although the two companies' combined cut of the royalties was larger than I liked, and so we shifted to publishing on Amazon KDP directly. It was an arrangement that seemed to work for all parties - I could write without worrying about anything more than what made a good book, readers could buy what they liked to read in whichever format suited them, and companies could make money facilitating this. Everyone was happy, not that there was any reason why anyone shouldn't be - after all, my books featuring nothing more scandalous than loving couples enjoying themselves.
If only things could have remained so simple! Instead, we've faced a variety of issues, some so bizarre and nonsensical that one couldn't have made them up! These can be divided into three categories: censorship, pricing, and technical, all of which have been an unwelcome distraction from what I want to do, which is to write about sexual submission in a healthy, wholesome way.
From February 2016 onwards, some of our books were available through Google Play, which allowed them to be easily purchased on phones and other devices running the Android operating system. This wasn't because of any deliberate decision to sell them through this channel, but simply because Lulu had started enabling it by default. At the start of March 2017, a reader enquired whether the rest couldn't be made similarly available, and, being happy to oblige, I arranged for this to happen. Their satisfaction was short-lived, because the very next day, Google took offence to one of the already available books:
It has come to our attention that your Content, titled “Padlocked Until Playtime: Submissive Women Frustrated By Female Chastity Belts,” violates the Google Play content policies.
“Reason for removal: We do not allow images of sexually suggestive or explicit nudity on the covers of books except in limited non-erotic contexts. We also don't allow sexually explicit terms or excerpts in the titles or descriptions of books.”
Your book has been removed from Google Play.
padlocked until playtime had been updated in September 2016, and thus had been being sold through this channel without issue for over six months. Had the policy changed, or was it only applied belatedly? Assuming that the drawing of the chastity belt and bra on the cover was not “sexually suggestive”, one is left searching the book's description for “sexually explicit terms” that could have warranted the removal. Should I have been more coy when writing about the desperation of the heroines, rather than daring to use such outrageous words as “pussy” and “dick”? One can only wonder whether the censors would have reacted the same way had I been writing about a detective searching for a missing cat!
If you'd like to judge for yourself, this is the text that Google took issue with:
When a woman is stopped from having sex, she wants it all the more! It's hard for a girl in heat to think of anything else when she's hot to trot, with her predicament made all the more agonising when she's prevented even from playing with herself. No matter how hungry she might be for something stiff inside her, however, a chastity belt will make sure she stays unsatisfied, saving even the most promiscuous of women's passions solely for the man who keeps her key.
Whether aroused at the office or feeling horny at home, there's no doubt that the four heroines in these stories about female chastity will remain denied and deprived, each becoming desperate for dick because of the device locked around her body. Forced to endure the frustration of steel after being made to wear a chastity belt by her husband, a submissive wife learns that a good girl does as she is told and lets her master take the lead, having no choice but to stay chaste when her pussy is padlocked until playtime.
Curiously, Google's language police had no problem with cocks, locks and lingerie, which not only contains what my dictionary describes as vulgar slang in its title (it's not about chickens!), but also in the first two paragraphs of its description (which, because of technical limitations at the time, were all that would have been considered). Moreover, the cover artwork is, to my mind at least, more suggestive. Unlike padlocked until playtime, it was never removed - until I took the decision to have all my books removed from Google Play, as a protest against their prudish policy.
In January 2019, we published two books about male submission, open wide for your wife! and loads to swallow. Reflecting the subject matter, open wide for your wife had cover artwork featuring a man wearing lingerie and stockings being presented with a spoon containing white liquid, whereas loads to swallow had a stylised glass of milk. Of the two, the latter was far less suggestive - indeed, out of context, it wouldn't have raised the most prudish of eyebrows, although I hoped that potential readers might see it as rather more exciting! In any case, both books were approved for distribution by Amazon within twelve hours of being submitted, not that I had expected otherwise.
Two days later, however, Amazon took issue with the glass of milk:
We’re contacting you regarding the following book:
Loads to Swallow: These Feminized Men Face More Than a Mouthful of Milk! by Masters, Emily (AUTHOR)
During our review process, we found that the cover image is in violation of our content guidelines. Our content guidelines apply to the book interior, as well as cover image, title and/or product descriptions. As a result, we cannot offer this book for sale. If we identify additional submissions with similar content that violates our guidelines you may lose access to optional KDP services and/or face account level actions up to and including termination.
The content guidelines referred to gave no indication as to why the cover image had been rejected - indeed, they asserted that Amazon provided their “customers with access to a variety of viewpoints, including books that some customers may find objectionable”. They did, however, “reserve the right not to sell certain content, such as pornography or other inappropriate material”, although the glass of milk could hardly be considered such! Nevertheless, I had my artist hurriedly prepare an alternative cover, featuring a silhouette of a wineglass and a stylised bra, and also had the spoon removed from open wide for your wife!, in case that also caused offence. I had assumed that the books could be resubmitted, subject to a second review, and then sold again.
Instead, Amazon had marked loads to swallow as “blocked”, preventing anything from being changed. It couldn't even be deleted, instead reduced to a mark of shame! An enquiry asking how revisions could be made in order to bring the book into line with the content guidelines (making no mention of the fact that those guidelines said nothing about why the book had been blocked) was initially met with an automated response advising that Amazon needed up to five business days “to review everything”. Rather than offering a way forward, however, their belated answer was unhelpful:
We've confirmed that your book(s) contains content that is in violation of our content guidelines and we will not be offering this title for sale on Amazon. As stated in our guidelines, we reserve the right to determine what we consider to be appropriate, which includes cover images and content within the book.
If you wish to re-publish your book(s) with content that meets our guidelines, it will need to be submitted as an entirely new book and go through our standard review process. Previous customer reviews, tags, and sales rank information are not transferable because the title will essentially be a different product.
Remember that our enquiry had not asked for the previous version to be reviewed, but rather had merely wanted to know how it could be revised. Apparently that was impossible, leaving the choice of submitting the book again, despite not knowing what guidelines it had broken, and risking “account level actions”, or giving up on Amazon and hoping that people wanting to read it on a Kindle would accept the slight inconvenience of purchasing through other channels. I chose the latter, and am pleased to say that many readers did. Were it not for not wanting to encourage any other authors to use Amazon, however, I would like to offer the “inappropriate” artwork for use in a recipe book. I doubt anyone would have given it a second thought were it titled “healthy smoothies”!
open wide for your wife! remains available to purchase on Amazon, as do a variety of books on similar subjects by other authors. Amazon also sell unashamedly pornographic videos, with covers that are barely less explicit for any strategic pixelation of otherwise naked, carnally-engaged bodies - many receiving their own helping of milk! If loads to swallow is more to your taste, rest assured that the paperback, PDF and EPUB versions deliver the same protein-packed punch, and can be purchased from all the other marketplaces.
In March 2015, we published bimbo, secretary, ballerina, bride. Again, it was approved for distribution by Amazon within hours. Over four and a half years later, in October 2019, after many sales, Amazon changed their mind:
During a quality assurance review of your catalog, we found that your book(s) are resulting in a disappointing customer experience. Indicators of a poor customer experience may include customer refunds and feedback. As a result, the following book(s) have been removed from sale on Amazon:
[bimbo, secretary, ballerina, bride]
We encourage you to listen to customer feedback and be proactive in making changes to your books in the future order (sic) to minimize the likelihood of customer disappointment. Reasons for customer disappointment may include but are not limited to: content that is too short, typos, formatting issues, etc.
As a reminder, since publishing books with disappointing customer experience are (sic) against our guidelines, we may suspend or terminate accounts that repeatedly try to do so.
Like loads to swallow, bimbo, secretary, ballerina, bride had been “blocked”, making it impossible to revise. Amazon's unwillingness to help find a way forward wasn't limited to threatening account termination again, however. An enquiry about where the book might fall short of their quality guidelines, and what could be done to resolve the matter was met with the instruction to “resubmit it as a new book”, but without any further details about why Amazon had suddenly rejected it. Nor did the customer reviews offer any insight - it wasn't a stinker, by any standards. Indeed, the correspondence I had received from readers was very positive. Despite scrutinising the guidelines, we could find nothing that was amiss, technically or otherwise, with this particular book. Like all my other fiction, it had four stories, each over ten thousand words long, without any obvious typos or formatting issues. Had an odd pattern of refunds tripped some automatic algorithm? Or was there some theme or phrasing that Amazon had decided they no longer liked, with “disappointing customer experience” being merely a pretext? We will never know, because they wouldn't tell us.
Fool me once, shame on you. Fool me twice, shame on me. We had published two new books earlier in October 2019, but I decided that these would be the last that would be available through Amazon. Fortunately, it's easy to convert the EPUBs into the special format that Kindles are restricted to using, allowing you to continue to read my books - blocked or otherwise!
I would be saddened if readers thought that brassièred was nothing more than a cynical money-making exercise, as is unfortunately too often the case with sites aimed at sissies. Starting with my very first book back in 2010, we have made almost all of the non-fiction available to read, in its entirety, for free on the website, because my aim has always been to promote a realistic, healthy approach to the subjects I cover. As I say elsewhere, if even one reader finds their relationship changed for the better as a result of having access to books that they wouldn't otherwise read, the lost sales are a small price to pay. Of course, sales are always welcome, and I make no pretence at writing stories out of charity! I certainly don't write them for the benefit of multi-billion dollar companies, instead expecting a reasonable proportion of the royalties.
What is a reasonable proportion? For a physical book, there are obviously printing costs. For electronic books, the various distributors bear the costs of download and payment processing, as well as customer support. Let's see how that works out in practice, ignoring any sales taxes that might be taken:
|Paperback||Lulu take 20% after printing costs||we receive approximately 55%|
|PDF from Lulu||Lulu take a $0.99 flat fee, then take 10%||we receive approximately 80%|
|EPUB from Lulu||Lulu take a $0.99 flat fee, then take 10%||we receive approximately 80%|
|iTunes through Lulu||Apple take 30%, then Lulu take 10%||we would received 63%|
|iTunes||Apple take 30%||we would receive 70%|
|Nook through Lulu||B&N take 50%, then Lulu take 10%||we would receive 45%|
|Nook||B&N take 30%||we would receive 70%|
|Google Play through Lulu||Google take 52%, then Lulu take 10%||we would receive 43.2%|
|Google Play||Google take 30% or 48%, depending on country||we would receive 70% or 52%|
|Kobo through Lulu||Kobo take 55%, then Lulu take 10%||we would receive 40.5%|
|Kobo||Kobo take 30% or 55%, depending on price and currency||we would receive 70% or 45%|
|Amazon KDP through Lulu||Amazon take 57%, then Lulu take 10%||we would receive 38.7%|
|Amazon KDP||Amazon take 30% or 70%, depending on price and currency||we receive approximately 70%|
Some of the royalty options have an insidious twist, limiting the higher percentage to particular price ranges. In the case of Amazon, a book must be priced between $2.99 and $9.99 to qualify for 70% royalties, limits that haven't changed since we started publishing on KDP in 2014. Sadly, inflation hasn't been anywhere near zero over that time, nor is it likely to be in the future, yet there is no indication that Amazon will change these limits to reflect the inexorable devaluation of the dollar. What does that mean for a book that one might like to price at $19.99? There is no point putting in twice as much work to warrant the higher price, when the 35% royalties will be the same as 70% royalties on a book priced $9.99. Such a pricing system instead encourages authors to write in ways that aren't in the interest of readers - for instance, by splitting a book into many short parts, each having to be bought separately. It is hardly surprising that the market is flooded with short, cheap rubbish, leading to a genuinely disappointing customer experience!
What do these companies do to justify taking so much, other than being picky about naughty words? They don't do any production or promotion - they merely accept files that other people provide and make them available for download through their store website or application, taking advantage of their dominant market positions. Is that really comparable to the effort that authors spend writing? I think not!
Looking solely at the figures, it would seem to make sense to avoid intermediaries such as Lulu where possible. Ideally, we would sell the electronic books directly, but that would come with its own complications about handling payments. Every marketplace adds its own demands - not just in preparing and uploading the required files, images and text, but also such delights as tax documentation.
Using an intermediary isn't a panacea, however, adding further delays to what can often be a lengthy wait for approval. In 2020, it was taking several weeks for newly published books to appear on iTunes and Barnes and Noble, although it wasn't clear exactly who was to blame. Far from enamoured with the royalty rates, I was already wondering whether this was worth the trouble, especially when two books, girdled for me and falling in love with lacing, seemed to get lost in the system. Lulu helped make my decision by announcing that to “facilitate this review process”, they would be charging a one-off fee of $4.99 for each book submitted. Although this was a token amount, it was too much - I refused to pay for the privilege of receiving poorer royalty rates, and thus we stopped published new books through these channels. Both Nooks and iOS devices can use our EPUBs without needing any conversion - you just need to download a file.
In December 2022, we increased our prices for the first time in twelve years. Doing so is a surprisingly time-consuming process, requiring each book to be individually changed, but one doesn't need to worry about that when one has a secretary! Unfortunately, even though everything else about them remained exactly the same, Amazon regarded the repriced books as having been resubmitted, and thus required them to pass their approval process again. One failed to do so, not because of any naughty words or pictures this time, but for the strangest of reasons:
During our review, we found that your book contains interior and/or cover content that’s available from a different publisher. We need you to confirm your publishing rights before the book is made available on Amazon.
His Wife His Mistress: Tales of Men As Maids and the Women They Serve by Masters, Emily (AUTHOR)
To publish the book(s), reply to this email and send documentation and/or verification showing you hold rights to the content. Please submit any documents you have, along with an explanation of any previously published books within 5 days. If we do not receive the appropriate documentation, the book(s) will be unavailable for sale on Amazon.
At that point his wife his mistress had been available on Amazon for almost eight years, but now we were being asked to provide “a letter from the previous publisher reverting rights back to the author”, “a signed copy of the agreement between you and the author” or other similarly preposterous documentation - simple proof of copyright was apparently not enough! While I could have had my secretary produce plausible paperwork, my previous experiences with Amazon left me disinclined to humour them. Instead, I treated their request with the contempt it deserved, and ignored it. A week later, Amazon blocked the book, patronisingly adding a bonus note about the importance of prompt responses to their by now familiar threats to account status - something which, as we shall see shortly, is important only when it suits them:
Thanks for your interest in using KDP. We haven't received a reply to our previous message regarding the following book(s):
His Wife His Mistress: Tales of Men As Maids and the Women They Serve by Masters, Emily (AUTHOR)
As a result, the book(s) listed above has been blocked from sale on Amazon. To avoid publishing delays, it’s important that we receive a prompt response to our messages.
If you still want to publish the book(s) listed above, review our previous message and address the requests we've outlined. If you're having difficulty finding the message, check your spam or junk folder.
As a reminder, all content submitted through KDP must comply with our terms and conditions, content guidelines, and copyright guidelines. Repeated submission of books that do not comply may negatively impact your account status. You may also lose access to optional KDP services.
Curiously, it was still possible to purchase his wife his mistress through Amazon, albeit with a different ASIN (Amazon Standard Identification Number). If you were to have done this, we would have received royalties - not directly from Amazon, but through Lulu! Yet Lulu's systems didn't believe that they were distributing the book to Amazon, not least because we told them to stop doing this in 2014. For some reason, the previously distributed version of his wife his mistress, along with nine other books, reappeared in March 2021, yet it was the only one of the ten that Amazon took issue with. Who knows why? Not wanting to earn further marks of shame, nor having the slightest confidence in Amazon's customer support's ability to get to the bottom of the issue, I was loath to ask!
Perhaps I should have done, because in August 2023, Lulu sent this;
Lulu has terminated your access to your accounts pursuant to the terms of our Membership Agreement. Your final royalty payments will be forthcoming as set forth in the Agreement.
We were notified by one of our distribution partners that your content violated the terms and conditions, so that is why your account has been suspended.
Observant readers will note the absence of any details in this unpleasantly brusque email, the full text of which is included above. At a stroke, all of the paperbacks, PDFs and EPUBs had disappeared, leaving would-be purchasers limited to the Kindle versions. That turned out to be ironic, because when asked what could be done to reverse their decision, Lulu revealed that Amazon was the distribution partner in question, and his wife his mistress was the content that was supposedly in violation of their terms and conditions - except that, after reviewing the issue, Lulu “determined that Amazon was incorrect to flag your content as violating terms and conditions”. The account was thankfully reinstated, and the books were available again, albeit only after each had been republished - another time-consuming process, and one that had the side effect of removing those that had been available from iTunes and Barnes and Noble. The only silver lining in this sorry tale was that the phantom copies have disappeared from Amazon too, although without knowing what caused them to reappear the first time, I cannot be sure that they won't cause problems again!
While I am not party to exactly what Amazon sent to Lulu to trigger such a heavy-handed response, it is plausible that it was a similar demand for proof of publishing rights - something that would suggest copyright violation if one didn't know any better. In a world there are no doubt dishonest people trying to pass off other people's work as their own, and where the legal consequences of that might be borne by the publisher, it is perhaps understandable that the latter might shoot first and ask questions later, but that didn't make the experience any less unpleasant. I can only be glad that Lulu's customer support is more competent than Amazon's, even if I was left unimpressed by their unfriendliness.
Readers can rest assured that we won't be increasing our prices on Amazon again any time soon, not only because of this issue, but also the royalty limits. If Amazon don't increase those to account for inflation, I will have the remaining books removed instead.
Royalty percentages are meaningless unless those royalties are actually paid. Fortunately, that's a process that ordinarily works like clockwork. Lulu send an email on the 17th of every month, whereas Amazon send multiple notifications on the 20th in advance of actual payment on the 29th (albeit after an extra month's delay), one for each country in which sales have occurred. Like other emails from Amazon, these notifications aren't especially helpful, because unlike Lulu, they fail to include the one piece of information that authors really want to know - the amount that is going to be paid! Nevertheless, it is reassuring to be informed that everything is proceeding as it should.
In April 2023, however, Amazon failed to send any notifications. An enquiry about whether payments would be made, if so when, and if not, what might need to be done to resolve any problem, received the following, unrelated answer:
Due a technical issue, there is a delay in sending the KDP Select Global Fund and All Stars Bonus Update for March, 2023. We will send the email as soon as we can. In the meantime, you can view the March, 2023, update in our Community forum
Had a customer support representative misread the enquiry, or had they simply clicked on the wrong button when choosing a stock response? On challenging its unhelpfulness and reiterating the questions about whether and when payments would be made, Amazon sent another stock email, this one even more infuriating:
It look like your response was blank.
To help us understand your issues, can you share additional details around the issue?
And on challenging that, reiterating the initial enquiry for the third time, they failed to reply at all. So much for the importance of prompt responses! That left us having to look to the KDP Community Forum for possible answers, not that one would expect to find anything authoritative there, as much as some of the regulars seemed to like delivering disdainful advice. One poster suggested that up to fifty thousand authors had been affected, but even if that wasn't the case, we certainly weren't alone. In a way, that was relieving, even though no-one knew what was happening, let alone what could be done about it - not even those who had received more relevant emails from support representatives.
Amazon finally sent out payment notifications on May 1st, with payments being made the following day - only a couple of days later than usual. Even so, the experience served to worsen my opinion of their customer support still further.
I am fortunate in that I don't have to worry about the technical complexities of publishing, having such matters taken care of for me. It's wonderful to see what I've written appear on the website, in print, and in electronic form, even though I can't begin to understand the magic that makes that happen. If only other systems could be as flexible, instead of eliciting curses from my wizard when their requirements clash with mine! Why, for example, must an EPUB have most, but not all, of the words in its title capitalised in order to be accepted for distribution? That's not what I want, and it isn't necessary for paperbacks or PDFs, but EPUBs apparently have more stringent standards. Why is it not possible to allow readers access to a book in both formats once they have purchased it, rather than selling each separately? I am told Smashwords, an alternative publishing platform, would permit that, but at the cost of submitting the books in a proprietary format that would lose niceties such as our special font - akin to copying out a piece of calligraphy in crayon in order for it to be copied again.
Then there is the question of why Amazon don't allow EPUBs, the industry standard for electronic books, to be read directly on Kindles, but instead require them to be converted. The answer is not a technical one, I am told, but rather seems intended to dissuade readers from purchasing books from other retailers - a cynical business decision that puts bolstering their bottom line before customer convenience. Fortunately, the conversion is easy, but the few moments it takes are a few moments that you shouldn't have to waste so that authors like me can choose companies who treat us with more respect.
If you're a reader, you'll likely have your own preferences about how you buy books. I know from my correspondence that many people like to purchase from particular stores, favouring familiarity over setting up new accounts. By not using certain companies, I am asking you to go out of your way in order to read what I have written, even if only slightly, something that sits uneasily with me. I hope that, understanding my reasons, you might be persuaded to support companies who work with authors, rather than those that behave unreasonably.
If you do, thank you! Your support of my writing is greatly appreciated!
Unsurprisingly, restricting where my books are sold has negatively affected sales. While I have fans who eagerly await my next publication, there are also more ambivalent readers, perhaps those who are taking a gamble on me as an author they have never read before. Indeed, it's easy to imagine people not seeking to buy my books in particular, but rather searching for something that tickles their fancy in their favourite store, and who'll never see anything that isn't published there. The material on the brassièred website attracts many, but not appearing on popular marketplaces obviously comes at a cost.
I could, of course, decide to put up with being poorly treated, but tolerating bad behaviour only encourages it, be that with a maid or a multi-billion dollar company. Contrary to what Amazon appear to believe, customer service should be about providing a service to customers - something understood by companies who want to keep their customers. To illustrate the difference, we have had cause to contact Lulu's support on a number of occasions over the years we have been using them, and they have always been helpful. Contrast that with Amazon, who have not only failed to solve even a single issue for us, but have often been outright hostile. The difference is like night and day, it being clear that Amazon regard authors as being, at best, disposable, and, at worst, adversaries to be repeatedly threatened with account termination.
Why might that be the case? One might consider a leading marketplace disproportionately attracting opportunists seeking to make a quick buck with scant regard for readers or rules, not helped by royalty arrangements that encourage quantity over quality. Equally, one might imagine support representatives being motivated by metrics other than customer satisfaction, especially if providing such support were regarded as an unwelcome cost to be minimised as much as possible. Why pay more for staff who take the time to properly read emails, let alone resolve problems, when there will always be new authors wanting to take the place of disgruntled ones? One can see from the use of “book(s)” in the stock emails I've quoted just how little regard Amazon appear to give an author's individual problem - indeed, it has been suggested to me that their first line support representatives may not be able to do more than pick from a set of such emails. That would, in turn, encourage a vicious cycle where there is no point in trying to explain nuanced details to them, quite unlike an intelligent interaction where both parties work towards getting a resolution.
Then there is the chilling effect that having to meet unspecified guidelines has on writing. Google don't provide a list of the “sexually explicit terms” that they don't permit in descriptions, leaving authors having to guess whether the likes of “pussy” are too prurient for them. Amazon's guidelines are even more inadequate, only stating that they won't sell material they “deem inappropriate or offensive”. Rather than gambling on what that might mean, authors might understandably restrict what they write. I know that I avoid certain themes that I am sure my readers would enjoy, themes that authors yet to be bitten don't think twice about. I find myself refraining from using particular words for fear of upsetting an unthinking algorithm, even though there's nothing remotely wrong with them in context. You can forget a book about male chastity featuring pictures of how devices should fit, as helpful as that would be for readers. Before one knows it, one's writing about couples making love in the most oblique of ways, yet at the same time, Amazon sell movies that depict depraved violence and sadistic mutilation - mainstream “entertainment” that will never be blocked for being “inappropriate”.
If you're wondering whether or not to use Amazon KDP to publish erotica, or indeed, any other sort of book, my answer would be simple: don't. If you do, however, don't expect consistency from them, either between your own books, those of other writers, or other products. Don't expect to be able to make changes to your books without problems, and don't expect those problems, or any others, to be resolved. Don't expect a fair, undistorted market for your work, and don't expect all your books to remain on sale. You needn't take my word for this - a search for the experiences of other authors will yield many similar stories. But do consider using alternatives who appreciate you more!
Whether you're a reader or an author, I'd be very interested to hear your experiences purchasing or publishing erotica. I'd also invite representatives of the companies that we no longer use to contact me if they'd like to address any of these issues, although I don't expect anything to come of that invitation!