your buggin'
Your bugging or your buggin' is a way of saying that the person you are talking to made a dumb statement or is crazy.
Matt: where can I download more RAM?
Sean: your buggin'
Sean: your buggin'
Your buggin
Basically your doing too much/being extra but usually not meant in a good way
If I smacked someone in the face for stealing my cookie then I would have said "Your buggin"