The supposed bone that is the cause of a "boner." When a male becomes aroused, the pubocockus bone moves from a position between the abdominal and pelvic cavities inside of the abdomen to the shaft of the penis. The presence of this bone in the penis makes it hard and, hence, a "boner" ensues.
Oh crap! That ho' kicked me in the junk and broke my pubocockus!
by Jahorgasen November 20, 2006