21 Inches of Dick

So I'm driving down the highway with my friends Collin & Billy. We are in a hurry and going way too fast and of course we get pulled over. A lady cop walks up to the window and asks for license and registration.

Me: "Problem officer?"

Lady Cop: " You boys were doing 110 in a 60, that's reckless driving and I'm going to have to take you in."

Me: "I'm SO sorry but we are in a real rush, is there ANY way you can give us a warning? I promise not to speed anymore."

Lady Cop: "I'll tell you what, I'll let you go scott free if you three can show me 21 inches of dick"

Me, Collin, & Billy talk amongst ourselves and agree we may as well give it a shot. So I pull out 10 inches, Collin pulls out 10 inches, and Billy pulls out 1 inch.

Lady Cop: "okay boys, thats 21 inches you're free to go"

We continue driving for a while in silence, all pleasantly surprised to not be in jail, when Billy leans forward from the back seat and excitedly says. "That was close! 21 inches on the money! Aren't you glad I had a boner!?"

Note: This joke is much more effective in person, if you have a childish sense of humor, and if your dipshit friend is the butt of the joke (and preferably doesn't know he will be).