What is the origin of the idiom "kiss my ass" and when to use it?

The origin of the idiom "kiss my ass" is not precisely documented, but it is an expression that is considered vulgar and offensive. It is used to convey strong disapproval, annoyance, or disdain toward someone. While the exact historical origins are not clear, it is a phrase that has likely developed over time as a crude and impolite way of expressing anger, contempt, or disregard for another person.