"Actions or verbiage designed to confuse the defense into believing the snap is not imminent, are not legal. This includes pretending to have a problem with the play that has been called, an equipment problem with a shoe, the ball, etc. and feigning an injury. A good rule of thumb to follow is that if an act appears to be unfair, it is probably contrary to the rules."
That came from Redding I think but am looking for original source