((Okay, for openers, the key is to introduce your character and give your partner something to work with. To bulk up your posts, you could add more about how your character is feeling, maybe the actual dialogue between the boys giving the dare and how you get to the dorm. Just things to think about. ^^ I hope this is more helpful than it is mean.))
Alicia blinked and looked at the man on her bed. "Ummm...can I help you?" she asked, wondering what he was doing in a dress. Then again, it wasn't the strangest thing she'd seen. She flipped some of her long, blonde hair over her shoulder, her amber eyes taking him in. She stood up and tilted her head to the side, clearly confused by his presence in her room. She had been drinking, however, and was a little too tipsy to really question his presence deeply. She was more curious than anything. She was 5'6'' and curvy, but still slender. The girl watched him now, wondering what he might say.
((sorry if that was too repetitive.))