This is an excellent exercise for releasing pressure and stretching lower spine. To perform it you will need a fitness ball.
Go on your knees and place your hands on a fitness ball. Push the ball away from you and feel the stretch in your back. At this point of the exercise your upper body is parallel with the floor.
Roll the ball with your hands towards body and straighten it with your head up. At this point your upper body is vertical with the floor.
Repeat this