An alternative way to get some thoracic extension is to stretch over the back of a dining or hard chair. It helps to have a towel draped over the back of the chair and then to tuck your low back in to a neutral position. Rest your hands behind your head and stretch back over the chair.
Then move your bottom forward on the chair and stretch again so that you get slightly lower down on your spine. Move your bottom forward again to get lower down and stretch again.
