Sinful Press focuses on publishing erotica. They primarily publish eBooks but most are also offered in paperback format (through print on demand publishing). Sinful Press is based in the UK. They are a relatively new publisher and so far their Amazon sales have not been stellar, but what they have published has largely been well reviewed. They also have better covers than most presses of this kind.
They will be temporarily closing to submissions at the end of June 2018, so if you do want your manuscript to be considered by them, you must submit it to them before this time.
They are specifically requesting more diversity in their submissions. They are interested in older characters, LGBTQ+, ethnic minorities, or disabled characters, they are not interested in stories that fetishise any of the above.
Their website implies that they offer advances for all novel length work, but it doesn’t go into any details. Novella length work is accepted, but no advances are offered and they do not publish print editions of novellas.
They offer 40% net royalties on digital and print, and 20% on audio. If they do not make an audio version of your book in one year, those rights revert to you. It is important to note that on net can be a tricky term to use (though most small presses do), so make sure they are clear in the contract about the details of that.
To submit, send 5-10k words of your novel or novella in a .doc or .docx file, with a query letter attached. Please include a bio.
To learn more, please visit their website here.