Sit upright in a chair with your weight through your seat bones.
Move forwards so your back is away from the back of the chair.
Separate your feet and knees and place both hands on top of your knees.
From this position, slowly roll back slumping your weight through your tail bone.
Your shoulders will round but keep your gaze straight ahead.
Roll forwards again on to your sitting bones, opening up the chest and shoulders as you go.
Repeat this cycle at a steady pace.