I have a idea, for a aunt and nephew RP. The nephew (your character), he's sended away from home, by his parents. He goes far away, for living with his aunt. He doesn't know any one at his new school, he's mad at his parents. And a little, at his aunt too.
His aunt, she's very pretty, but shy and quiet. She isn't married, and doesn't have a boy friend. She dresses very conservative, most men don't even notice her.
Some thing happens one day, with the nephew, and his aunt. Maybe she's lonely, and horny, and she seduces him? Or maybe, he sees how pretty she is really, and that he could manipulate her? But any way, they have wild sex, with each other.
After words, the aunt, she gets a big crush on her nephew. He's the first man, in a long time, that pays atentions to her. And, she loves the sex, with him! The nephew, may be he doesn't like her, the way she likes him. But he loves fucking her, and that she lets him do any thing, to her, all his dirty fantasies. And may be he gets off, on humilating her, and making her his slutty sex toy. The aunt let's him, because she's very desparate, for him being, with her! And she secretly loves, being humilated!
The RP may be has many Extreme things. It would be up, to you, for some of the things he does. We would need discusing first though?
If this is some thing you might want playing, please PM me. And tell me, what ideas you have, and what things you might want doing! Also please look at my O/Os, they may be help you know, what I like and don't like.