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