At around age 50 when mans testicles begin to sucumb to gravity, and are closer to his knees than his belly button.
Mike put his foot up on the bench after showering in the gym and unbeknownst to him his testicles swang out from below his towel and nearly slapped Tom in the face.

"Damn", Tom thought, "that nigga sure has got a low sac."
by Crack O Da Ass December 10, 2004
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