There is "technically" no right or wrong way for using the BackGuard since everyone's pain points and situation is unique. Placing the cushion wherever it is most comfortable and supportive for you is what's important.
This being said, here is our suggestion based off our own use and the feedback of many users.
What you want to do is to place the cushion between your back and your chair at the point where you need the most support. (Usually the spot in which you have back discomfort. For most users this is right on their lower back.)
Once you have the cushion between your lower back and chair, pull your chair in under your desk so that your body is as close to your table edge as possible. The pressure will cause the cushion to deflate to an appropriate size.
As soon as the cushion starts feeling "loose" and starts slipping a little, it means that your posture is getting worse and you're beginning to slouch and move away from your table.
For some users who prefer the cushion to stay in place, simply use the adjustable elastic strap. Now naturally the elastic strap has a stretch limit and will not fit all chairs but it will for most.
To lengthen or shorten the strap simply move the clasp to the left or the right.
If you find yourself really having to stretch the elastic strap even at its most elongated position then it is suggested that you do not use the strap as it might cause the cover to rip. (At the end of the day this is fabric!)
Still have additional questions? Just let us know : ) (here)