Preston Pitbull

A safety manuever used in a canadian penetentary setting. When forced to give prison felatio treat the other prisoner good and as soon as you hear the first sign of pleasure (usually a moan of some sort) lock your jaw as a pitbull would and jerk your head from side to side like a dog with a pull toy. This has two possible outcomes you get shanked or you never have to use this manuever again.