Cap'n Crunch mouth Share definition Flag When the roof of your mouth gets all torn up after eating Cap'n Crunch or some other rough food. I get Cap'n Crunch mouth after eating 2 bowls of that friggin cereal! Cap'n Crunch mouth by Carla Reyes January 11, 2008 0 0 Get merch Get the Cap'n Crunch mouth mug. Buy Now — $32.95 See more merch