Formula: If your index finger is 3 1/2 inches long, then to go "five deep" would equal 17 1/2 inches of penetration.
Lx5=P where L=Length of index finger and P=Penetration depth
Jared: "Why do you ask?"
Franco: "I was hoping to go five deep tonight, and she's the only bitch I know who's seasoned enough for that kind of punishment!"
Jared: "I'll kill you".