On your downswing, pull your left shoulder up and away from your chin. It sounds complicated, but it's an easy move. Try it where you are right now: Swing to a mock top position, and then pull your left shoulder up and to the left. Feel how the upward movement of your left shoulder automatically drops your arms and hands down. This is the "slotting" move common to all great power swings. It's like a water-skier being whipped around on a line by a boat. In this scenario, your left shoulder is the boat, and your hands are the skier.