Cum Gas Share definition Flag (n). 1. The often small but potent, oily like fart that you pass durring an intense orgasm. 1. "Austin, your Cum Gas smells so nasty, if that wasnt the best fuck i've ever had, i would punch you in the face." Cum Gas by LS returns(tiny) January 10, 2009 0 0 Get merch Get the Cum Gas mug. Buy Now — $32.95 See more merch