The Club is on an Inclined Angle and moves on that flat Angle (end over end - Gyroscope). The Plane. Can you Align the Plane? Yes. Trace the Baseline.
A simple drill to show how the Right Shoulder can move On-Plane and Downplane and support the #3 PP.
Address the ball. Add more Knee Bend. Move your Left Foot 6" away from the Plane Line. Start with short Strokes. You'll need to move closer to the Ball, but that shows how far away golfers normally stand, and always reaching for the ball with the right arm and shoulder. An On-Plane Right Forearm Wedge at Impact Fix will show you the same Ball Location as this drill.