A trucker picks up a hitchhiker who climbs up in the cab and notices a monkey on the dashboard.
After a few miles, he asks the driver what the monkey is for.
The driver says "I'll show you," and with that he hits the monkey with the back of his hand, sending the poor creature rolling across the dash.
The monkey goes down between the drivers legs, unzips his pants, pulls out his unit and proceeds to give the trucker oral gratification.
When finished, the monkey pulls out a tissue, cleans the driver up, puts everything back and jumps back up on the dashboard.
"See that?" said the trucker.
The man said, "Yeah."
The trucker ask the man, "You want to try it?"
The man said, "OK, but don't hit me as hard as you hit that monkey!"