Rough idea I want to throw out there; subject to revisal:
In Manhattan lies The Corruption. For most people, it's a just a sleazy dive club with a BDSM theme. But to an unlucky few, it's a trip into a world that will leave them forever changed.
The Corruption's real owners are a gang of succubi and incubi. They are forever on the lookout for virtuous mortals who can be captured and corrupted. While most of humanity are a potential idle amusement to them, it's the best of humanity that they truly hunger for. They use their magics to lure the mortals into the basement, where they are captured. Once taken prisoner, the succubi and incubi seek to corrupt them- to find their flaws, their dark desires, and to use them to ruin the mortal until they give in to their temptations. When a they are finally released, they have no memory of their time, except as a bizarre dream, but the damage to their souls is forever done.
In the basement lies a door that leads to their dungeon- a place that isn't limited by time or space. The dungeon runs on its own timeline, and while there prisoners never age. A mortal can be held there for a hundred years and still be returned on the night that he left when he has been twisted to his captor's liking. The dungeon is vast, but can only be accessed through the door in the night club, and only when one of the owners wants it to. Every kind of torture or sexual device imaginable can be found, including many unknown to mortals.
This game is about mortals being completely deconstructed by their captors. The mortals are put through whatever experiences the demons can concoct to break them, not just with physical torture but through psychological manipulation.
1) Free-form, exotic extreme roleplay. Anything allowed by board rules goes, aside from actual death (They are out to corrupt, not kill). The succubi may even have ways to give mortals experiences that would kill them otherwise, but keep them alive.
2) The mortals are shared among the succubi and incubi. There should be less pairing off and more mixing between roleplayers. I may have the head incubi "schedule" who is to give each mortal his next session (based off of OOC player agreement, of course).
3) I'm going to ask everyone that wants to play a mortal to play a succubi/incubi as well in order to keep numbers even. I don't want a dozen prisoners and 1-2 succubi between them.