[jerry1967]

Welcome to the forum tm.

I believe you might be thinking about Impact perhaps. The "on plane right shoulder" concept describes an Alignment associated with the beginning of the downswing, "Startdown". Basically, after you have bumped to the left in some manner assuming a full swing, your right shoulder (as opposed to your hands or arms) is the first component to "accelerate" and take the entire Power Package down plane towards the ball. The "period of shoulder acceleration".

When viewed from down the line, the angle from the ball to the right shoulder at Top is referred to as the "Turned Shoulder Plane". So the right shoulder is on this plane already by definition. Get the left arm on this plane too and where the right shoulder goes so goes the rest of it, ideally down towards the ball as opposed to out and over. Practicing this with "Start down waggles" is a great, great drill.

Hit the search function with some of these key words for more and most likely better information.

When you bump to the left, does this move drop the right elbow in front of the right hip and then the right shoulder goes down plane?