During World wars I and II,American foot soldiers were only issued about 10 individual squares of toilet paper to keep backpack weight and volume to a minimum.If a soldier needed to wipe his butt,he would take one square of toilet paper and fold it into quarters. He would then tear out a semicircular portion from the common corner which left a hole in the middle of the paper when unfolded.He would then stick his forefinger through the hole and wipe his ass with the protruding finger. The paper was grasped at the base of the finger with the free hand while the soiled finger was slowly pulled free of the paper.The contaminated square was then discarded and the corner previously removed was used to clean from under the fingernail.
When the toilet paper roll starts getting low,I will generally implement the G.I. butt wipe procedure.