This was a game played in the changing rooms, after the class had spent an hour and a half running around in freezing mud. Proceedings would commence by flinging a wet muddy sock into the air. If the sock landed on someone, there would follow a cry of, "Uuurgh! You got sock, mi lad!", and the game would continue.
There were only two possible end scenarios to this game. Either somebody would get beaten up, or a fight would break out. In either instance, acts of violence will be largely ignored by the games teacher, in a "let them sort it out amongst themselves" kind of way, faintly reminiscent of the interracial basketball match scene in the film Scum.