Just as we relax the hips and let the thighs wrap inwards, so we must pay similar attention to the point where the chest and shoulder muscle meet.
The shoulder well must be relaxed and hollow. To do this we have to soften and relax the chest so it is not pushing forwards ,up and out. As a result the shoulder blades open and the upper back is rounded. This should all be natural and not forced. It is not a deliberate, contrived hunching.
When we can do this our arms are integrated into the torso and will have ward off energy.