This movement is less about the shoulder and more about the upper arm and elbow. Do not lean forward into this movement! Move from the right hip and keep spine upright.
1. While you sit fully on your left leg, the waist turns slightly to the left and the right foot withdraws as both hands drift downward. The right foot is placed behind the left heel, the right hand is at the groin with the palm facing in while the left hand is in line with the left hip bone and below the dantian with the palm facing obliquely forward. Bow the right arm slightly.
2. The right foot steps directly forward weightlessly while bowing right arm and forming a small ball in front of the navel rotating the left hand to the top of this ball.
3. Pour weight slowly into the right bow right arm more and push left finger tips toward inside of right elbow. Feel like the left hand pushes forward and inflates a sail with unseen wind. Attention is over right shoulder. Feel like you are pushing a heavy object with your right forearm.