You're the only girl in the slytherin group, they treat you as a princess and you all have fun making pranks on each others.

The boys were in the forbidden forest at night because they couldn't sleep, you were in the same situation and decided to make a prank, becoming a big snake with the animagus.

Lorenzo and Draco: AAAAAAH!

Blaise and Regulus: take out their wand STAY AWAY SATAN!

Mattheo and Theodore: drop their cigarettes in terror

Tom: BASILISK? makes love eyes