The holster lanyard, called a leg tie or leg thong, secures the bottom of a holster to the leg. This holster configuration allows for a quicker draw and it keeps the holster close to the leg, keeping it from bouncing around and reducing the risk of catching on something. In today's world, the leg thong is still used by competative quick draw shooters. Many people keep the leg thong on their holsters but tie them in decorative knots to add character and style.
Adjust the leg thong so that it passes through the holster with about 3/4 of the thong on one side and 1/4 of it on the other side.
Fold the longer end back on itself along the shorter piece. You now have three lengths of the thong lined up with one significantly longer than the other two.
Wrap the long piece around the other two lengths close to where the thong passes through the holster.
Continue wrapping the longer end back on itself and the other two lengths. You will end up with a spiral wrap along the back until you reach the end of the wrapping piece.
Pass the end of the wrapping piece through the loop you created near the short end of the thong.
Pull the thong tight at the holster end of the wrap, drawing the loop through the wrap back toward the holster.
Pull the short end of the lanyard through the wrapping. This will draw the wrapping up tight against the bottom of the holster and leave you with a decorative knot on your leg thong.
This knot is a variation on the hangman's noose knot; it has more wraps, but the technique is exactly the same. Play with the lengths you start with to get the best results. Ideally, you will end up with relatively equal loose ends once you have tightened the Knot.