Curiously, at our school, you had to put your thumb to your forehead (index and little fingers raised like horns), and demand that your associates "eat that fart". They in turn had to put thumb to forehead, and the last to do so did indeed have to simulate eating the fart. Also curious was the fact that our fat mate Greg always used to be the last, and would invariably fly into a 'red rage' whereupon you ran like hell in case he caught you and pummelled you to death. Oddly enough this sequence of events no longer occurs in the office full of thirty somethings with which I now spend my days.