ass smack
Ass smacking is when someone is smacking the ass of another person, usually using their hand or some other method.
Sometimes it is used to show disapproval or anger towards the victim of the ass smack, however it can also be used in a erotic manner such as invitation for sex. Can also be used for comedic effect.
Ass smacking typically consists of a single playful slap, in cases where there are multiple rough and painful slaps use the spanking tag instead.