This is a technique I use to breathe while I’m shaking—to stop my shaking. I have tardive dystonia, a condition which causes muscles to move without my asking them to. When I move one muscle, other muscles move without my asking. When I breathe, the movement of my breathing causes other muscles to move—to contract—keeping me shaking. Big belly breathing helps me stop shaking. Maybe it will give you some stability, too
Big belly breathing is diaphragmatic breathing—in big belly breathing, you breathe from your diaphragm. If you don't know about diaphragmatic breathing, read about it first
To big belly breathe, start by breathing in and extending your belly as you do it—as though your belly contained the air you breathe in
Then, keeping your belly pressed out, breathe all the way out
Continue breathing while keeping your belly pressed out. keep your belly still while all the other muscles move around it
This allows me to breathe without my breathing causing other muscles to contract
Try it—does it give you some stability, too?