Actually two different ideas that will be run somewhat seperately, the basic function is as follows:
Lilith is a succubus, ancient and powerful. Some say she is the cast-off woman who insisted she was equal with Adam before he demanded that god make him a subservient one, though if asked her usual comment is something to the effect of "The world didn't start that way." In her long ages she has seduced all sorts of people, in a wide variety of circumstances, and her experience and skill is beyond measure. Suffice to say, in the modern era she has become quite bored. She can have anyone she wants, at just about any time, and it makes the experience pretty hollow. Because of this she's taken a step back from her usual 'work' and started training other succubi and incubi (though their base gender is really more a preferance than an actual limitation). For her favored pupils she has designed a gambit of tests of successivly higher difficulty, a series of people in particular circumstances that they need to seduce. They will be given a set time limit, and if the person ever rejects them so strongly that to continue would require them to harshly rape them, that demon will be disqualified from the test, and sent back to the regular training.
Of course, just watching and waiting is not very interesting for Lilith, so she's come up with a challenge for herself.
Now, while it is true that she can force anyone to copulate with her, she cannot force every man and woman to truly enjoy the experience, it is true she has mutch skill, and when she uses her magic she can make them feel whatever she wants, but that, again, is boring. And so she's made a set of tests, like a much harder version of the ones she has created for her students, with an additional rule... None of her lovers are allowed to climax until they beg to. Of course, every time she fails, she can easily start over, and she does not have a large problem doing so, as this is, after all, to keep her entertained and kill time.
In the long run, there will be a larger story that ties all the various threads together, and likely a lounge and an office where they can talk to the other students, talk to Lilith, er... Practice if they want, and such. Also, in the long run, I could use some volunteers to play some angels >_>
I'm looking for some students, and someone(s) willing to play Lilith's targets, any takers?