The result of a badly-timed, pre-toilet-roll-shop poo in which the only surface with which you can clean your shitty arse is the palm of your hand
You've just got out of the shower and feel the familiar rumblings of a forthcoming diarrhea attack so after making sure the toilet door is locked, you sit on the toilet and unleash the fury, legs spasming uncontrollably and all. When this violent exchange is concluded you look around and to your horror see that there is no toilet roll. You think about using the good towel but decide it isn't worth your life so you close your eyes and send your palm to it's untimely, shitty death. Shitpalm.