Lean an alignment stick against a chair, following the club's plane above your trail shoulder. Swing back feeling the club travel just underneath the stick, around your body. Alternate rehearsals and gentle real shots.
Down-the-line: the club goes up outside the hand line with little torso rotation; at the top the hands are very high, above the functional plane.
Frequently asked questions
What is the "Under the stick roof" drill for?
Flatten a backswing that's too steep
How do you do the "Under the stick roof" drill?
Lean an alignment stick against a chair, following the club's plane above your trail shoulder. Swing back feeling the club travel just underneath the stick, around your body. Alternate rehearsals and gentle real shots.
How long does the "Under the stick roof" drill take?
About 15 minutes per session, 12 reps.
Sources
David Leadbetter — The Golf Swing
Dr. Young-Hoo Kwon, Texas Woman's University — Golf Biomechanics Instructor Program (secuencia cinemática, plano funcional)