Wiktionary
moose knuckle
alt. 1 The ball joint of the humerus in a moose's skeleton. 2 (context slang English) The noticeable shape of a man's penis when he is wearing tight clothes. n. 1 The ball joint of the humerus in a moose's skeleton. 2 (context slang English) The noticeable shape of a man's penis when he is wearing tight clothes.