Buttock

The buttocks or "gluteus maximus" (sometimes just "glutes") are the two masses of muscle and fat covering the posterior aspect of the human (primate) pelvis. They allow humans (primates) to sit upright comfortably without resting weight on their feet, as (for example) cats and dogs do when they sit upright.

They belong to the intimate parts.

In many cultures, corporal punishment is traditionally delivered on the buttocks. This is especially true for lighter punishment and domestic discipline. The probable reasons is that such punishment when applied to the buttocks can be made quite painful yet remain harmless to the culprit's health.

Exposing the bare buttocks as a protest or for fun is called mooning.