a dedicated cloth, used when hiking for extended periods of time, used for wiping your ass. If used properly, there is very little if any odor, and a 12" x 12" ass rag will last for weeks. It is carried hung outside of the pack. A term originally coined by Ron Hood of THE HOODLUMS fame, a outdoor and survival website .
johns Ass Rag was clipped to his pack. He used it to wipe his ass after taking a crap inthe woods.