An extra scrotum with which some men are born. It is located behind the primary scrotum and does not have its own testes; it is an extra empty sack of skin. It gets its name because it sometimes "dingles" down to the butt hole and gets shit on it, dingle-berry style.
Poor Mike tried to take a dump in the woods while camping and got shit all over his dingle because it hung down in front of his anus as he was squatting. On the bright side, he didn't need toilet paper.