Think of some dumb question and knock in the door. Watch girl reaction and keep talking. If you made everythingthen come into her room. Look around, there you'll find several useful items that may be used for her pleasure. Therefore, if you are lucky and brave enough then you are going to get excellent sex.
Meet with another girl from the hall. She's sexy and it's quite simple to seduce her. So throw some compliments about her body and she'll spread her legs.