Dirty Chalkboard Share definition Flag While having anal sex, the man removes his penis and draggs it accross a white wall. What's that brown line on the wall from? It's from the Dirty Chalkboard I did last night. Dirty Chalkboard by Tom July 1, 2006 0 0 Get merch Get the Dirty Chalkboard mug. Buy Now — $32.95 See more merch