You could also hit on her. Nothing physical where you can get into legal problems, but make her uncomfortable.
Just walk up and tell her “we need to get togther while my roommate’s out.” Be serious and meet her eyes.
If she says “fuck you,” or “no way” just say “ok” and walk off.
She’ll most likely call you an asshole and leave, or you will fuck. I give it 25% chance you’ll fuck.
I’m actually dead serious about this. I used this approach on a roomate’s girl I couldn’t stand.*
- She called me an asshole and left.
She has drunk booty called me before. She is fat. We keep her around because she has sorority sisters.