Well... I like when a girl who is stronger than me hits me. Not like, intending to hurt me, but a playful punch or something. I don't know how to explain it.
I also have a thing for legs. To me, breasts and ass are completely irrelevant if the girl has nice legs. If she's got nice legs and everything else is great too, those are just a bonus.
I also like girls much shorter than me, and dark hair (or red hair) and pale skin.
Oh, and this confuses me. In my class, there's this girl who is only book smart, and not very fun to have an intelligent argument with. Me and one of my close mates enjoy political debates and the like, so when those happen in U.S. History class, we have a field day. She is always on the opposing side of us (our views are more right wing, her's more left wing). Something about arguing with her, getting under her skin and annoying her gets me excited and I've started fantasizing about her. But, I can't stand the girl.