One day little johnny gets twenty dollars from his dad for doing some housework
His dad says asks little johnny "What are you going to do with the money?
Little Johnny replied "I'm going to use it for a prostitute"
On the way into town he meets grandma who upon finding out what the twenty is for tells him to give her the twenty dollars and they can have sex
He goes home and his dad say's "That was quick!"
And Little Johnny says "Oh' I just gave the twenty bucks to grandma and we had sex."
His dad says "What you fucked my mom?
Little Johnny replied "Well hell you fuck my mom why can't I fuck yours?"