Maybe you've run into this problem too? Your options are: 1.) Call for help. 2.) Scream for help. 3.) Imitate MacGyver and fashion a butt-wiping device out of the toilet paper roll, some chewing gum, and whatever you have in your pockets.
This graphic is from a T-shirt design by Glenn Jones (aka Glennz). He does great work; I have a couple of his shirts in the closet right now.