Out of gas

A little girl asks her mum,
'Mum, may I take the dog for a walk around the block?'


Mum says,
'No, because the dog is in heat.'


'What's that mean?' asks the child.


'Go ask your Father. I think he's in the garage'.


The little girl goes to the garage and says.
'Dad, can I take Susie for a walk around the block? I asked Mum but she said the dog was in heat and that I should ask you.'


Dad says,
'Bring Susie over here.' He takes a rag, soaks it with gasoline, and scrubs the dog's rear with it and says, 'OK, you can go now but keep Susie on the leash and only go onetime around the block.'


The little girl leaves and returns a few minutes later with no dog on the leash.


Dad says, 'Where's Susie"'


The little girl says,
'Susie ran out of gas about halfway down the block and there's another dog pushing her home.'