When you are wearing a jacket zipped up all the way to the neck, with hands in pockets, waiting to kick the shit out of someone, as seen in the movie Green Street Hooligans.
John: Why the hell is that guy standing like that? Does he not know he's about to get the shit kicked out of him?
Steve: No you tosser! He's Greenstreeting. He'll beat the fuck out of that mick bastard.