This is one of the major problems facing beginning skiers - turning with the upper body. Here is an example of turning with the upper body - he's leading the turn with the upper body and twisting the skis with little or no edging:
In good skiing, we need to decouple or separate the upper body movements form the lower body. You need confidence and discipline: the confidence that you can make the skis turn otherwise and the discipline to do just that.
If we look at the range of rotation of upper body, this is an extreme of Rotation, since we have a leading of the turn with the upper body, then Square, which is more passive in nature and then Coiling which is effective movement.