Trunkbutt is the slang term for the medical condition known as a prolapsed rectum. This unpleasant, and unsightly condition can be caused by medical problems (specifically bacterial infections) or via the sexual overuse of the rectum through the long-term practice of anal intercourse. In the case of sexually induced
trunkbutt, the pulling motions of the penis or other phallic object causes the ring of muscles of the anus to gradually protrude outward. The reality is that this malady looks nothing like an
elephant's trunk. It cannot even be considered the closest
approximation. But it does take its name from the mighty elephant.