When you have Sex in a nasty truck stop bathroom while the girl holds her hands and legs on the walls like Spiderman to avoid touching the floor and the Shit on the bottom of the walls.
"My girlfriend and I were driving home and decided to stop at a gross truck stop for a quick fuck, But there was trucker shit on the floor and walls so she had to do a Dirty Morgan so I could hit it from the back."
when you are a ranger and go to your boyfriends house and give head while his sisters friends are over and you decide to do it in the living room until it hurts.
when you're holding up your phone and making faces at it, as though you are taking a selfie, but you're really taking a picture of the person across from you or the wall or anything else that seems interesting but you don't want to be caught dead taking a picture of.
This action is often made more convincing by wiggling the eyebrows or opening the mouth, to pretend you're trying to get a Snapchat filter to work.