When Julie came out after sucking 5 consecutive dicks in the shag room, Sam instantly started making pecking motions and yelling, "Cluckcluck! Cluck cluck!"
A shortened version of the response to "Quack quack seat back", usually when small children are around. Full phrase is "Cluckcluck, i dont give a fuck"
Person 1: I gotta go to the bathroom, quack quack seat back
a drug addict who doesn't possess the monetary means to support their habit. A "cluck" will often try to scrounge drugs, or small amounts of money to buy drugs, from anyone they know. When they engage in this behavior, the resemble chickens that cluck, peck, and scratch for any morsel of food they can find.
That sorry-ass cluck tried to borrow the change out of the ashtray in my car so he can get high.