A little girl
A little girl asked her Mom, "Mom, may I take the dog for a walk around the block?"
Mom replies, "No, because she is in heat."
"What's that mean?" asked the child.
"Go ask your father. I think he's in the garage.
The little girl goes to the garage and says, "Dad, may I take Belle for a walk around the block? I asked Mom, but she said Belle was in heat, and to come ask you."
Dad said, "Bring Belle over here."
He took a rag, soaked it with gasoline, and scrubbed the dog's backside with it and said, "Okay, that should take care of that problem. You can go now, but keep Belle on the leash and only go one time around the block."
The little girl left, and returned a few minutes later with no dog on the leash.
Surprised, Dad asked, "Where's Belle?"
The little girl said, "She ran out of gas about halfway around the block, so another dog is pushing her home."