There was a tour bus on the rez that stopped at this trading post. The tourists are all walking and looking at the surrounding area. One tourist looks at his watch, but it is broken, so he leans over to a native who is squatted down next to his horse. "What time is it, sir?"
The rez dude reaches out and softly cups the horse's genitals in his hand, and raises them up and down. "It's about 2:00," he says. The tourist can't believe what he just saw.
He runs back to the bus, and sure enough, it's 2:00. He tells a few of the fellow tourists his story, "The man can tell the time by the weight of the horse's genitals!" One of the doubting tourists walks back to the rez dude and asks him the time, the same thing happens! It's 2:05.p.m.
He runs back to tell the story. Finally, the bus driver wants to know how it is done. He walks over and asks the rez dude how he knows the time from the horse's genitals.
The rez dude says, "Sit down here and grab the horse's genitals. Now, lift them up in the air. Now, look underneath them to the trading post, where that clock is hanging on the wall."