From the Buckaroo Tradition website.
Step by step instructions on tying the Buckaroo Square knot, also called The Double Mustache knot, The Highwayman’s knot, and in Texas; the Gun Man’s knot. There are several ways to tie this knot, but I found this method works best for tying a horse’s tail. Note: The directions are written for trying the knot with two hands and no camera. Since I photographed this myself, I had to switch hands in some photos.
1. Comb the tail and divide into two equal sections. Keep the comb within reach; re-comb the right side until smooth.
2. Hold the right section in your left hand starting at the end of the tail bone, wrap it around 2 fingers on your right hand, by laying the section over your fingers and winding back to front; one wrap. Hold loop in place with your right thumb.
Photo 3 shows a side view of step two.
3. With your left hand, comb the left tail section smooth, taking care not to catch any of the right side loop. Gather the left tail section in your left hand and slide it UNDER the “tail” of the loop on the right side and wrap it around the back and to the front. Continue to wrap in front by crossing the left section OVER the “tail” on the right side.
4. Pull the left section through the loop from step 2. (In the photo, I used a section of insulated copper wire to help pull the tail through the loop.) Dampen knot and cinch it down tightly. Tradition dictates the knot be untied at the end of each day before returning your horse to the cavvy or remuda.
