The new Charlie the one who is now twerking that ass and is only 16 years old.

When you take a huge shit in a tube sock and beat someone with the sock filled with poop.

When you and your girlfriend end up banging in the car so fucking hard that the condom breaks, getting her pregnant.

When some one goes around dry humping girls

When you kill your ex and have sex with the corpse

When a man gets bored with regular anal and decides to slide his nuts into the pussy. This is a suave move with a few stipulations. The chick's vagina should be close to her ass. Otherwise you're tugging on your ballsack. Never let her help, women have nails and can't feel the pain. And once you're in, don't jackhammer, you have to rock in a smooth motion or start again.

A dirty charlie is when you put a handful of mud in a sock and tell your friends it's shit. They'll eat it looking forwards to the smokey goodness and be disgusted to find that the brown substance is in fact mud and not shit.