Lie on your front with a pillow between your thighs. Fold your hands and rest your forehead on them. Your shoulders should be open and relaxed, your toes together and your heels apart. Breathe in, feeling your spine lengthen. Breathe out, gently pulling up your tummy muscles, keeping your hips and pubic bone on the floor. Squeeze the pillow with your inside thighs, and gently tighten your buttocks. Breathe in keeping it all held in position, then breathe out and relax.