Modifications to sex rules from Book of Unlawful Carnal Knowledge (BoUCK)
The physical states concerning sex are: Unaroused, Aroused, Peak, Climax.
The mental states concerning sex are: Normal, Horny, Lustful, Over Stimulated, Sexual Delirium.
It's in the rules how to go through the physical states. It's the rules for the mental states that are confusing/annoying. So, here are the rules I'm using as a base. If you want different rules for you game, we can discuss. I'm perfectly fine with that.
If you are Unaroused, you are Normal. It's as simple as that. If Aroused, you are also Horny. It's as simple as that, unless you've climaxed recently. Then you could be Aroused, and cooling off. Lustful is when your focus is on a single person, to the exclusion of others. An example is someone in love with another, or someone with Charm Person affecting them. Overstimulated and Sexual Delirium are where it's slightly confusing. So, Overstimulated happens when either A) you are peaked, but should have orgasmed a number of times _in a row_ equal to your CON modifier, but didn't, or B) you've done the opposite, and orgasmed a number of times equal to your CON modifier _in a row_. If you resist becoming Overstimulated, then you get a Fortitude Save, the DC increasing each turn you are stopped from orgasming, or orgasmed, _in a row_. The DC is based off the Sexual Prowess of the 'opposing person'. The Save DC can never be above 20 + 'opposing' Sexual Prowess _Rank_.
Example: Person A has Teasing Lover sex trick. Person B has a +1 CON modifier. Person A uses Teasing Lover on Person B after they are peaked. Person B now rolls against a DC 13 Fort Save. Person B rolls a 14, and barely avoids Overstimulation this round. Person A uses Teasing Lover again. Person B must now save against DC 16. The highest it can go is DC 26, for Person A's Sexual Prowess Rank is 6.
I realize this favors people with high CON, but A) sex seems to be a high CON, high CHA situation in D&D, and B) you should have decent CON anyway, because _more_ HP never hurt anybody who has them.
Once you are Overstimulated, you are in danger of becoming Sexually Delirious. If you are stopped from orgasming, or have another orgasm, then you must roll a Will Save. This Will Save is 10 + the Arousal DC modifier of the Arousal check you orgasmed from. If you fail, you are Sexually Delirious. If you succeed, then you are not, and get a bonus to resist if you orgasm again next turn, equal to half your Sexual Prowess Ranks (+1 if none or 1.).
Example: Person C has made Person D Overstimulated with orgasms. Person C now rolls a Sexual Prowess Check DC 25. Person D fails, and is in danger of Sexual Delirium. Person D rolls against a DC 25 Will Save, and fails. Person D is now Sexually Delirious.
If you want different rules, PM or Email me for discussion, and your games rules will be different.
Sexual Trick From Book of Erotic Fantasy (BoEF)
Instant Recovery
Prerequisite: Quick Recovery, Sexual Prowess 6 ranks, Con 14+, Male
Effect: You instantly recover from climax, and can keep going. You go from Climax to Aroused, if you want.