an expression used by people under the influence of marijuana when they feel that someone has completely ruined their good mood, or "killed their high"
here is an example
in a car*
Andrew: man, this is some good shit!
Eric: yea, it is- HOLD ON! DUDE! I JUST SAW A COP OVER THERE! HIDE THE BUD
! HIDE THE BONG
John: *looks for the "cop"*; what the fuck, thats not a cop, thats just an old lady in a white lincoln
Andrew: Eric! wtf!! your killing my high! stop being so paranoid.