"Mom, may I take the dog for a walk around the block?" a little girl asked.

"No, I don't think so. Fifi is in heat," replied the mother.

"What does that mean?" asked the child.

Embarrassed and not wanting to get into a biological discussion with her young daughter, the mother said, "Oh, just go ask your father. I think he is in the garage."

The little girl goes to the garage and says, "Dad, may I take Fifi for a walk around the block? I asked Mom, but she said that Fifi was in heat, and that I had to come talk to you."

Not wanting to have the biological discussion either, the father said, "Bring Fifi over here."

He took a rag, soaked it with gasoline, and scrubbed the dog's rear-end with it.

"Okay, now you can go for a walk but keep Fifi on the leash and you can only go around the block once."

The little girl left, and returned a few minutes later with NO DOG on the leash.

"Where is Fifi?" her father asked.

"She should be here in a minute," advised the daughter. "She ran out of gas about halfway down the block and another dog is pushing her home."