Facing Up to Bunker Shots
Knowing the mechanics of a bunker swing is important, but it’s even more important to know how the club works through the sand. If you understand what the bounce on the bottom of the wedge should do, you’ll intuitively make swings that skim more and dig less. There’s simple connection between the bounce and the face: When you can see the face, the bounce is doing what it should do. My favourite way to reinforce this is to smear washable finger paint on the face of a wedge. Set up with your hands slightly back at address and the face open so you can see the paint, then make swings so that you can still see the paint at the finish. If you’re digging too deep, the paint will get wiped off.
(reference: James Kinney, Golf Digest)
Paint Golf Aid