When a stray rugby ball is kicked towards an unwitting victim, it is considered good manners to shout "Heads!" to warn them. The natural response, rather than covering the head, is to look up towards the oncoming missile, resulting in a comical face/ball interaction and many tears.

Matt, who kicked for the first 15, had honed his skills to the point where he could place a ball into a crowd with unerring accuracy. He also perfected the timing of the cry of "Heads!" so that people would look up at the exact moment of impact.
written by Th* Boy *ucker, approved by Matt