Scumbag chess tricks, how to cheat at chess in a tournament setting. (Thanks, Dad.)

This trick works best in a time scramble where both players are quickly pushing pawns forward. The pawn on h2 is pushed very quickly to h4 and the clock banged, now return your hand over the same pawn, next move push the pawn forward again but this time leave it half on the sixth and the fifth ranks, bang the clock and return you hand over the pawn, on the next move the pawn is advanced to the seventh rank and a new queen next. I have seen this trick played by an old member of the Hull Chess Club many years ago to win the annual blitz tourney.

From this page: Benjamin Franklin's The Morals of Chess.