[Frances Phelps]

Is the issue stepping behind with the right foot, and then pivoting on the left heel? I would try isolating that movement, and practice it repeatedly without involving your arms until you feel comfortable with it. Get yourself into a shoulder-width or horse stance, and make sure your upper body feels relaxed. Then put your right foot behind you, but before your turn, relax into that standing leg to make sure you can balance comfortably on that leg. Then you can try turning and pivoting on your left foot.