I've been kicking an idea around for awhile now, for an RP involving a pair of high school students. The female, who I'd prefer to play, is a pretty young woman who tends to dress in black, wears dark makeup, and is what most students call a "goth." The male would be a big player on the school teams, popular and a complete womanizer. He also considers himself sort of a connoisseur, and has been with lots of different types of girls.
As for the story, our jock sees the new girl at school and realizes he's never been with a girl like her before. He's a manipulative, cunning hunter, and will do anything he can to seduce her. He's very liberated, and isn't embarrassed about sex at all- quite the opposite of the innocent, relatively shy young woman he's after.
Once he's finally gotten his way, either consensually or (more likely) through some kind of manipulation, he wants to have some fun with her, and begins to make her "his". He might make her dress differently at school or bring her to parties where he shows her off. From there on it can go wherever you like.
Check my on's and off's, let me know if theres anything you'd like to add, and let me know if your interested!