Mudnuts Share definition Flag A condition where fecal matter gets on your nutsack after taking a nice healthy shit and then wiping your ass from back to front. That shit on your underwear doesnt look like skid marks, i bet its from mudnuts!!! Mudnuts by IBStudent April 22, 2006 0 0 Get merch Get the Mudnuts mug. Buy Now — $32.95 See more merch