A game played by two individuals (usually bored Navy Sailors) involving a 12 inch standard wooden ruler. The participants drop their pants and stand butt to butt. They then each insert the opposing ends of the ruler into the crack of their ass and clench butt cheeks firmly. The participants then shuffle away from each other while trying to retain possession of the ruler. The person who retains possession of the ruler by clenching and shuffling wins that round of Butt Tug.
"Man my ass is so firm from getting ready for the Butt Tug championships next weekend."