wash your mouth out with soap

Wash your mouth out with soap is an older phrase which is said when you want to make it a point that someone should stop using profanity, lying, biting, tobacco use or a type of verbal disrespect. While all of these occurrences are accurate for the use of this phrase, it is most commonly said to someone using profane or vulgar language. It comes from the idea that parents would punish their child for speaking in this manner by literally putting a bar of soap in their mouth.