This is one of the funniest jokes I've ever thought : Johnny (or, again, whoever you want) will use his fingers for this one. He must be behind somebody, he rises his thumb and, fastly, put it in the guy's ass (try to hit the hole). This joke can be done with more than one finger :) .... The following one is a little bit less original, but it's good: it's called the "ass-divider". It's really simple, but funny as hell : Johnny goes behind a member of the crew and, really fastly and forcibly, grabbing the viewable part of the guy's underpants with both hands, pulls them up as much as possible, in order to hurt the guy.