I was visiting a friend in a faraway land, and we found this piece of paper with a crude drawing in her office. She recognised it immediately, as the funniest / cruellest prank ever. I don’t think I really get it.
Apparently, you draw a picture of yourself rubbing your bum on someone’s door and leave it on their desk. They will be stuck wondering whether you really did rub your bum on their door. Will have to try this and see if it really is as hilarious as it’s meant to be.