Golf: How To Play The Ball Below Your Feet

Step 1: The set-up

Place the club head behind the ball, aiming left of the target.
Stand with your feet wider apart than in a normal set-up, and bend your legs more.
This gives you a lower body position, allowing your swing to reach down to the ball, which is further from your eyes and body than normal.

Step 2: The swing

Keep your weight on the balls of your feet throughout the swing to maintain your balance on the slope.
Bending your legs keeps them more or less immobile, so the main movement involved in the swing is a turn of the upper body.
The upper body rotation is just like in a normal swing, centered on the spinal axis and leading the motion of your arms and hands through the swing.
Maintain the angle of your upper body through the entire swing to be sure that your club swings low enough to reach the ball.
If hitting from a very steep hill, you should close the clubface at set-up to compensate for the effect of the slope on the flight of the ball.
So stay low, and hit the ball nicely onto the green.