Little Johnny and Suzie play on the swing set every day after school. One day, little Johnny goes home after school and asks his father, "What’s this thing between my legs, daddy?" His father replies, "That's your truck, son. You want to park that in a girl's garage"
The very same day, Suzie goes home and asks her mother, "Mommy, what's this between my legs?" Her mother smiles and replies, "That is your garage, honey. You NEVER want to let a boy park his truck in there."
Both of the kids go to school the next day, and like always, they play on the swing set afterwards. Suzie goes home after a while, and her mother is shocked to see blood all over Suzie's face and clothes.
"Suzie, What happened??" She cried. "Oh nothing, mom. Little Johnny tried to park his truck in my garage, so I bit off his back two tires!!"