A reverse pivot occurs in the backswing when the golfer straighten his or her back leg and shift their body weight to the front leg, and the upper body tilts toward the target instead of away from the target. This motion inhibits the amount of torque a golfer can create on the backswing. You need to learn how to rotate your upper body away from the target on the backswing to create maximum turn and leverage. This uphill lie drill will give you the feeling of what the top of the backswing should feel like.

Using a step, bench or a ball , place your foot on the riser so that your upper body is automatically tilting away from your target as if you were on an uphill lie.
Practice making backswings, keeping the spinal tilt away from the target. Keeping the back knee flexed will help.
Do the motion for 8 to 10 repetitions.

A reverse pivot will put a tremendous amount of pressure on the lower spine, which can cause pain or injury.

This is an isometric exercise that will train your muscles on the correct movement. Repetition is the key to correcting the motion.