I remember reading part of a story a while ago, but with my best searching I can't find it again. Hoping somebody here recognizes it. The premise was that a guy brings a girl to a party on their first date. I think it was a frat party, but I'm not positive. Things are going fine at first, but she's extremely competitive. If someone challenges her, she'll do anything to show them up. Long story short, she winds up having sex in front of her date to prove her skills. Does this ring a bell for anybody?
