What's That Noise ?

A firefighter was working on the engine outside the station, when he noticed a little girl nearby in a little red wagon with little ladders hung off the sides, and a garden hose tightly coiled in the middle.

The girl was wearing a firefighters helmet. The wagon was being pulled by her dog and her cat.

The firefighter walked over to take a closer look. 'That sure is a nice fire truck,' the firefighter said with admiration.
'Thanks,' the girl replied.
The firefighter looked a little closer. the girl had tied the wagon to her dog's collar and to the cat's testicles.
'Little partner,' the firefighter said, 'I don't want to tell you how to run your rig, but if you were to tie that rope around the cat's collar, I think you could go faster.'
'You're probably right, but then I wouldn't have a siren .'

Thanks Doug