This is when a guy and a girl or a guy and a guy, (no girl and girl because they dont have propper "tools")are haveing anal sex and right before the guy cums into the guy/girls ass he pulls his "tool" out and the partner rolls on their back and the first guy draws a smiley face with his cum on his partners chest.
Dan: I heard that Adam gaveMatt the dirty lathrop last night
When you’re doing a puzzle with some girl from out of town, one piece is missing at climax. So she fists your mouth, and tells you your phallus is like a babies arm.
About to finish my first 1,500 piece puzzle with some strange and realized I was short a piece, so she Dirty Lathan-ed me.