Execute the move after a forward step. The spiral turn always takes place after one foot moves in front of the other. This forward step sets up the foundation for the spin you will make by creating a balance point.
Turn toward your free foot. This is the foot that isn't forward. Place all of your weight on your forward foot. This is the balance point. During the spin, your forward foot becomes the pivot upon which your body turns.
Lift your free leg and wrap it behind your standing leg. Push off with your free foot as you do this, which gives you the momentum you need to get started. Your arms should be at least slightly elevated to act as a balance point. Your weight remains on your forward foot, with the back of the foot elevated almost to the point where just your toes are on the ground and your heel is up. After the initial push with your free foot, your body weight allows you to spin.
Squat slowly as you are spinning. When done smoothly, this creates a corkscrew effect. Allow your bottom to come as close to the ground as possible, creating the illusion that you are sitting. When you've developed enough strength, you will be able to go all the way down and back up again.