Johnny With A Cop On The Traffic Light

A cop on horseback is at a traffic light, and next to him is Little Johnny on his bike.  The cop says to the kid, "Nice bike you got there. Santa bring that to you?"

Little Johnny says, "He sure did!"

Then the cop says, "Well next year, you tell Santa to put a tail light on that bike."  

Johnny replies, "Nice horse you got there. Did Santa bring that to you?"

The cop, to be cute, says, "Yeah, I guess he did."

Johnny says, "Well, you tell Santa next year to put the dick under the horse, not on top."