cum n' run Share definition Flag When one very stealthly cums on someone without the other person noticing It was disgusting. I looked on the back of my jacket to find that I had been a victim of a cum n' run. cum n' run by Harry "gMan" G......... September 24, 2007 0 0 Get merch Get the cum n' run mug. Buy Now — $32.95 See more merch