Ethiopian Lip Plug:

A lip plate, also known as a lip plug or lip disc, is a form of body modification. Increasingly larger discs (usually circular, and made from clay or wood) are inserted into a pierced hole in either the upper or lower lip, or both, thereby stretching it. Today, the custom is maintained by a few groups in Africa and Amazonia. Some scholars have argued that in Africa, labret fashion boomed because slave traders refused to purchase slaves whose appearance was not considered "pristine" for the prospective buyers.