One of the oldest and best practice drills involves wedging a towel or headcover under one armpit and trying to hold it there during part of the swing. The SlotShot, an ergonomically-shaped piece of foam attached to a lanyard, works even better. If you’re a right-handed golfer, hook the lanyard clip to a belt loop near your left hip. Next, position the SlotShot (blue side facing up) under your right armpit (for left-handers, gray side up under the left armpit). Make sure there’s no slack in the lanyard. On the backswing, you should feel tension in the lanyard across your chest. Through impact, the device should drop out from under your armpit.
The SlotShot is simple to use and provides immediate feedback while you’re hitting shots. And, slicers take note: It’s impossible to make an out-to-in swing while keeping the SlotShot in place.