When playing a competitive game and the individual that is gradually losing scratches his/her head(Scalp) or facial features extremely fast due to the frustration of not being able to achieve victory. Hence... The gamer scratch AKA- The frustrated gamer.
Its a tie in super smash brothers 64 and link boomerangs and bombs the fuck out of pikabitch to achieve victory. Pikabitch fails to dodge several of links projectiles therefore initiating the "gamer scratch".
A skill developed by experience gamers, whereby one is able to scratch an itch at any point on the body faster than the speed of light.
It's so you don't lose any valuable gaming time by pressing pause, or just stopping for a second.
The hallmark of a lame nerd is the gamer scratch