What is Fucker Knuckles?
1.
In the game of marbles, the positioning of the clenched hand, with the thumb inverted into the clenched fingers, which propels a marble toward the target group of marbles. So called because of the hand resembling the common masturbation technique utilized by men, and because of the thumbs insertion into the "hole" resulting from the clenched position of the hand and fingers.
When I was a shorty, I was the Fucker Knuckle champion of the block.