On hands and knees, tuck your tailbone and round your entire spine.
Keeping your spine as round as possible, sit your hips back to your heels.
Breathe into your back. Can you expand the space between your shoulder blades as you inhale? Can you feel the area just above and below your bra-line move back as you inhale?
Keep your shoulders, neck and jaw relaxed.
Hold for 5 - 10 full breaths.