The basic idea is pretty simple, I'm looking for someone to play a young(ish) first time, Miko-archetype exorcist sent to deal with a house haunted by strange spirits and other lurking nasties. She soon finds herself at the mercy of one particularly mischievous spirit, that after overcoming her defenses (whether through seduction or something more coarse I shall leave until I discuss with the other participant), gives her a little present, transforming her from a pure maiden to a rather well equipped futa.
The rest of the story follows form there, her figuring out how to cope with her new state, new sensations, new lusts, and perhaps trying to stay pure in the face of the sexual corruption before her to succeed in her exorcisms. Or perhaps losing out to the temptations and corruptions and becoming the servant of this twisted place. Or its master.
PM me/respond here/talk to me on YIM as suits you if you're interested.
Also, I have a vague mock-up of a stat system loosely based on White Wolf/Exalted (kind of a work in progress) if anyone wants to try this out as a numbers game.