slap on the back

A slap on the back is the outward expression used when you want to show someone praise or approval or to congratulate them on a job well done. The slap on the back is more of a pat on the back rather than a slap which you would think would cause some sort of pain or discomfort. It is known as a universal sign for praising someone, and can also be used figuratively in which you use the phrase a slap on the back.