This exercise is perfect for golf, since it activates the obliques, strengthens core muscles and help to make a better turn and weight shift.

Roll down an exercise ball so that just your shoulders are on the ball.
Extend your hips, so that your thighs and torso are parallel to the ground.
Reach your arms up with your palms facing each other.
Slowly rotate the upper body to one side while keeping your lower body stable.
Repeat on opposite side.
Do 8 to 10 repetitions on both sides.
If you do not have an exercise ball, your can do this exercise standing.