A little girl asks her Mom, "Mom, may I take the dog for a walk around the block?"
Mom says, "The dog is in heat, go ask daddy."
The little girl goes to her father,
"Dad, can I take Susie for a walk around the block? Mom said the dog is in heat and that I should ask you."
"Hm." He answers, takes a rag, soaks it with gasoline, and scrubs the dog's butt with it.
"OK, you can go now but keep Susie on the leash."
Little girl goes and returns a few minutes later with no dog on the leash.
Dad asks, "Where is Susie?"
Little girl says, "Susie ran out of gas about halfway down the block. But another dog is pushing her home."