Impatient Dentist
When you are about to finish in a girl's mouth when she doesn't want you to, so she closes her mouth. Then you proceed to blow your load all over her closed lips like a dentist who's trying to get in someones mouth to clean but just gets pissed off.
Guy 1: "How'd it go last night?"
Guy 2: "It was hilarious. My girl wouldn't open her mouth when I wanted to finish. I couldn't wait any longer so I gave her the impatient dentist."
Guy 2: "It was hilarious. My girl wouldn't open her mouth when I wanted to finish. I couldn't wait any longer so I gave her the impatient dentist."