A Girl who dresses in a Velour tracksuit, dyes her hair blonde but has dark roots, has a fake tan and has a face that looks like a rodent.
See Jersey Shore.
Bro 1: Dude did you see that Rat slut in chemclass.
when you're holding up your phone and making faces at it, as though you are taking a selfie, but you're really taking a picture of the person across from you or the wall or anything else that seems interesting but you don't want to be caught dead taking a picture of.
This action is often made more convincing by wiggling the eyebrows or opening the mouth, to pretend you're trying to get a Snapchat filter to work.