Undershot

The sight of a man(nude) from his back side while bent over, exposing his testicles and hairy anus. Typically occurs inadvertently while adult movies are being filmed at certain angles. A very disturbing and surprising image if not expected; adult films should be required to give a 5 second or longer warning prior to displaying an undershot.

Derek: "Traci, check out this porn."

Traci: "Oh my god, look at that undershot!"

undershot

1.a waterwheel that uses a stream/river beneath to turn
2.to miss a target

undershot wheels