sharp sphere

Plenty of people within sexual relationships do sexual roleplaying with each other, to the point that it’s a trope. People are definitely interested in sexual roleplaying.

As for why there’s no TTRPG market for it, I can think of at least two barriers. One: people generally aren’t interested in doing sexual roleplaying outside the boundaries of an already-sexual relationship. Two: people who do sexual roleplaying within already-sexual relationships aren’t interested in buying a rulebook for it.

In casual sexual encounters, you’d never be able to expect someone else to know the rules, so even if they were interested, you’d have to teach them on the spot. In committed relationships, the structure of a ruleset is probably not necessary.

I could see there being a successful but small market, within the larger market of sex toys and games, for one-pagers that people in actively sexual relationships could buy to aid roleplaying with fun prompts or genre-specific character concepts.

It’s more of a stretch, but there are two groups of people who regularly do improv with strangers/acquaintances in sexual situations. One is porn actors. Kinda silly, but maybe there’s a market for a sex-TTRPG-based entertainment property in porn, in the style of D&D podcasts/shows. The other is cybersex chat room users. There could be something that caters to them, and chat rooms could facilitate connections between users that prefer particular systems, like you can do on Roll20 (“LFG”).

by force if necessary

they’re gonna love that sweet, sweet liability

Same. Finding an instance with the best community or matching interests felt silly when everything is changing quickly and discovery is still underbaked. I went with Lemmy.world because they seemed like the most capable admins.