A little girl was out with her Grandmother when they came across a couple of dogs 
mating on the sidewalk. "What are they doing, Grandma?" asked the little girl.
The grandmother was embarrassed, so she said, "The dog on top has hurt his paw, 
and the one underneath is carrying him to the doctor."
"They are like humans," said the little girl, 
"offer someone a helping hand and they screw you every time!"