1. When someone does something borderline homosexual to or around you, and you and/or one of your buddies decides to call them out on it. (Originated somewhere along the East coast.)

2. Commonly used comeback by douches on the East coast when insulted
1.

Campbell: "Dude does this shirt make me look chubby?"

Everett: "You gay brah?"

2.

Tourist: "God all these Jersey douchebags are starting to piss me off"

Guido from Jersey: "whoa, you gay brah?!"
by randlethemandle January 6, 2011
Get the you gay brah? mug.