A firefighter is working on the engine outside the station when he notices a little girl next door in a little red wagon with little ladders hung off the sides and a garden hose coiled in the middle.
The girl is wearing a firefighter's helmet. The wagon is being pulled by her dog and her cat.
The firefighter walks over to take a look. "That sure is a nice fire truck", the firefighter says.
"Thanks", the girl says.
The firefighter takes a closer look and notices the girl has tied her wagon to the dog's collar and the cat's testicles.
"Little Partner", the firefighter says, "I don't want to tell you how to run your rig, but if you tied that rope around the cat's collar, I think you could go faster."
The little girl replies thoughtfully, "You're probably right, but then I wouldn't have a siren."
 

hahaha