Redskins' Terrelle Pryor Goes After Chiefs Heckler: F**k Me? F**K YOU!!

Here's how NOT to take an L, brought to you by Redskins star Terrelle Pryor -- who went buckwild on a heckling Chiefs fan after their MNF game.

As he's entering the tunnel, the wideout drops an f-bomb and 1-finger salute on the heckler -- which got more K.C. fans to clap back.

But Terrelle REALLY lost it when the same guy called him a "little p*ssy" ... to the point where a team staffer had to step in and restrain him. At one point, Pryor acts like he's going to swing his helmet at the fan but stops himself.