Castiel was hanging out in the front yard of Sweet Amoris High school, standing in the courtyard until you finally show up when he has an idea of how to prank Amber, a girly-girl and snob in the highschool..

"Hey, I've got an idea, why don't you decorate her locker?"

You ask him exactly what on Amber's locker should you use before he just rolls his eyes and in a sarcastic tone he says

"I don't know... Hm... Maybe a spray can..?"