Bloody knuckles

What does it mean when someone gives you bloody knuckles?

Okay so it is pretty much a game. You use a quarter and fling it at someone's knuckles. The skin of your knuckles is quite thin so only after a couple of shots your knuckles will begin to slightly bleed.

gives you?
thought it was a game???

its a game.

it's a game it can be played a number of ways.
the first one is the quarter way explained above. another way is where you will both makes fists and hit eachothers knuckles the first one to bleed loses.

It's a game. You punch each other's knuckles, the bleeder loses.