May I ask you about your experience with practicing sitting straight?
I can't sit straight when I'm at my workplace. I'm trying, but sitting straight only when focusing all my attention on it. But when I draw my attention to tasks, my posture is as usual.
It can cause serious problems with your health and can irritate and erode your stomach. It's better to try lemon and see if it works for you. If you have no result, just stop doing it.