It's simply this. It is shit that does not come off your butt hole. You know how sometimes there is that little piece of shit that just wont come off well now there is a name for it. You have to just wiggle your ass a little to get it off or simply grap a piece of toilet paper and grab the poo and put it in the toilet (2 squares for best results.) If it does not come off then call a doctor ASAP.
Little tiny piece of shit like lets say the size of a golf ball that doesnt come off.