finally, the "more commentary."
the mechanics behind sex really need an overhaul. first, in non-prostitution sex, stamina decreases per orgasm. one of the sex perks increases the speed at which the player achieves orgasm. it seems the intention is to increase sex exp gain, combined with the exp gain per orgasm perk. this, however is outweighed by the downsides to orgasming.
foremost, other than EXP, there is no direct benefit to orgasming. only stamina cost. you only get positive rep from your partner orgasming. once you have the "speed" perk, you'll orgasm roughly twice as often as your partner does.
the issue this causes is exemplified by the optional part of the army quest "knock down the ESB and make them orgasm till they like you." without the speed perk, you'll spend your whole stamina bar to do this. with it, you have to sleep and spend a second whole stamina bar. well, barring you do not exploit the system and only use oral on them. if you never orgasm, you never lose stamina.
on that some token, if your partner never orgasms, you never gain rep. this makes oral acts preformed on you a waste of time, generally.
i can think of a few ways to fix the situation, varying in invasiveness from a series of relatively minor changes, to a complete and total overhaul. if nothing at else at all, the speed perk really needs to target the NPC, not the player.