#did a sex world setting once where sex demons engineered a contagious upper respiratory infection#but no raging boners instead it made peoples' mouths tongues and throats erogenous
Haha, I'm trying to wrack my poor old brain for the details. It's actually been a minor fascination of mine for a long time, long enough that I earnestly can't remember if I was inspired by this famous early porn movie or came up with it on my own.
I'm not 100% but I think I first used the idea in a fanfic¹. It all comes together really naturally, actually. "Sex pollen"² cuts the Gordian knot of "will they or won't they", but a direct impulse to have sex or "mate or die" felt bad to me on multiple levels, too much like coercion. Instead, just strongly incentivize a bit of "skinship". And a mild infection gives a character a fuzzy head, physical heat, swollen and sensitive mouth tissues, extra moisture, and an itch that felt really, really (just incredibly, elaborately) good to scratch, and hey boy, what's that in your pocket something that's the exact right shape and texture to hit those deep places. (A toothbrush was too rough, she tried.)
I may or may not have finished with the guy getting off again by performing oral sex, because his tongue is so sensitive. (These days I'd write it as 69 with a strap, to satisfy my sense of balance, but that would've been esoteric to me at the time.)
(1: I'd wager it was Akane with Ranma, but it could've been Ayeka and/or Ryoko with Tenchi, and there's an outside chance it was Breath of Fire II's Nina or Katt with Ryu.)
(2: Amusingly, 75% sure I hadn't actually heard the literal term "sex pollen" by then, which would've dovetailed even more neatly.)
The aforementioned setting would've been at least ten years ago, maybe fifteen, made for the "after dark roleplaying" board of one of the fantasy/anime/video games forums I frequented back then. I know it never actually saw the light of day, I think because the forum closed; but also because of my nature, I sit on projects for years at a time. I may have considered reviving it for some corner of 4chan (I loved the "quests" they did on /tg/, like episodic Choose Your Own Adventure stories with the choice made by popular vote), but I think that was around when they started getting huffy about adult content on blue boards, and none of the orange ones were hosting that sort of thing.
It was approximately an ISO standard fantasy setting except that people sought the mysterious ExoPrima energy (XP, naturally), which allowed them to improve their bodies or gain supernatural powers. People got a little from productive living, exercise, meditation, and a bit more from having good sex or from fighting somebody as strong or stronger than them, but they'd get the most from fighting a monster: creatures born of the raw flow of energy in the planet itself: EctoPrima. (I feel like I had some kind of pun on "mob" for them.)
But watch out! Lose to a monster (or a human with the Prima Manipulation power, which includes all strong XP hunters) and the winner can, for a time, influence the loser in order to harvest-generate a bit more XP (three guesses as to what form this mostly took), which frequently left the loser with a mutation or curse, sometimes a very durable one. A lot of hunters ended up with exotic features like horns, fur, glowing patterns and such. Also bad because a monster that gets too much XP from a human evolves. Opportunities to domesticate monsters were severely constrained: you can't limit one too much or it's cut off from the flow of raw energy, causing it to weaken and eventually dissolve into ectoplasm.
To finally wrap around to the subject, Demons were intelligent humanoid monsters. And they immediately saw the potential in humans (ie, giant bags of renewable XP). But they couldn't directly domesticate the humans either; weaken one too much and it's no longer a worthwhile source. But like fuck were they going to accept an even fight, so they had to find some way to make humans biddable and submissive. Cue using their own powers to create contagious sexual disease/curses, with the pretends-to-be-a-normal-cold tonsils-become-gspots disease as the most prominent. Get a human hot and bothered enough and demons get their ideal: a foe willing to start a fight, but is distracted and might half-way consciously throw it to get their needs met. And if the turns tabled sometimes, that'd just weed out the weaklings.
(I started one story in this setting. A hunter had managed for years with a demon curse that made most sex painful: Masochist's Dream. She's doing alright though, hunting and casually looking for a cure. But she's slipped up one day and got hit with "Heat": four days a moon of irresistible libido combined with an aura that attracts monsters. And now it's fused with the curse. Just going through it once made her go nearly insane with the contradictory urges, so she's desperate to find a treatment before it hits again.)
Thanks for the ask, I haven't thought about this in a long ass-time!