Dirty Derouin Share definition Flag The act of ejaculating (cumming) in a girl's ear during a blow job. Jeff: "I just gave this chick a Dirty Derouin"Steve: "Ew, Gross" Dirty Derouin by SkillzMcGruff December 2, 2009 0 0 Get merch Get the Dirty Derouin mug. Buy Now — $32.95 See more merch