When turning the body to the left, for example, the right foot would curl in, following that we rest our body weight to the right. Then the left foot is free to point to the left, followed by our body.
It is at this instance that we use force at our right leg to spin the hip and waist to the left. Then followed by the shoulder and arms.
It should be turning like a strong spring to create speed at the arms.
The tricky part is with the movement of the waist and hip. The movement must be forceful enough.