There Was Once This Cowboy...
The Indian replies, "Me tell time! Penis acts as sundial".
The cowboy in disbelief says, "Ok, what time is it"?
The Indian looks down at his "3:35..."
"That's amazing, your right!" the cowboy says in amazement. So he hops onto his horse and keeps going. Riding along further, he sees the same thing, gets off his horse, and thinking the last Indian was a fluke, asks this one the time.
The Indian looks down at his "one eyed bandit" and says "4:40".
The cowboy is stunned, the time was right again! Shaking his head he hops back onto his horse and rides again. After riding a while again, he sees yet another Indian on the ground with his "bald headed champ" except he was jerking off. The cowboy hops off his horse and says, "And what are you doing"?
The Indian replies, "Me winding clock".