Sit upright with your feet touching the wall either side of a radiator. Keep your legs straight and in contact with the floor at all times.
Lean forward from the waist, leading with your chest towards the radiator, if possible hold (gently) on with both hands to the radiator.
Hold for up to 3 min.
For a variation, place both hands on one side of radiator, whilst keeping both buttocks firmly on the ground.