I am 5 feet tall with a 2-year chronic low back pain from overworking with a computer. Unfortunately, I could not figure out how to make the Stretchit work for me. I went thru all the video clips and the forum discussion. I read that the cushion SHOULD be located around thoracic bones, although her demonstration video (with a folded chair) shows that it is placed between the end of thoracic and the top part of the lumbar bones and I also saw in the Forum that it is "OK" to overlap to lumbar bones. I expect there should be one instruction to make it work according to the inventor's understanding on bone/muscle structure.
I undertstand it is not supposed to be placed in the small (lumbar). If the bottom of the cushion is placed on the bottom of the thoracic bones, then the lumbar bones are not touching anything (i.e., the back of a chair)? So, the muscle around lumbar will get tighten up to stay upright??? The natural friction against the cushion (i.e., without intentional pressure against the cushion) is not strong enough to keep the thoracic muscle stay "hooked".
Currently, very uncomfortable regardless of where I place it... I really wish that this would help my chronic back pain, after reading so many good review comments. Before I return it, I'd like know what might be my problem. S.O.S. Thanks, in advance.