Women has menstrual cycle, while men don't have. Their sperm
will build up over time, and if it is unreleased, the testicle will
explode from the pressure of too many sperm.
hence, men have to whack off.
there are some guys who don't dare to whack off, and thus, their
balls explodes.
Thus, rise the origin of the phrase, "you have no balls", which
means you are a coward.
