Vampire Roommate

You share a dorm room with a guy who had always been cold and standoffish, mostly nice to others but especially allergic to girls – that was until he discovered you're a girl. It became a bone of contention between you, always bickering about your lifestyle habits. Today, he confronted you, and your argument turned into a magical lock-in where a 'make-up or never leave' sign appeared at the door.