1 definition by TheDirtyPillow

When having anal sex with a girl, the man pulls out and starts to write as many ancient letters of the runic alphabet on her back with his poo covered dick as he can before a) the girl notices or b) he runs out of the brown ink, at which point the man must try to masturbate until cumming before getting kicked out of her place.
Extra points are given if a coherent sentence is produced during the act.
Person 1 - "Dude, Sasha from accounting is looking super hot today"

Person 2 - "Okay Imma stop you right there, she is way too freaky for you"

Person 1 - "what do you mean? I would totally do her"

Person 2 - "look, I did a Dirty Rune on her last week and she just laughed it off. Don't go near her"
by TheDirtyPillow December 15, 2018
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