I know I can’t paint that design with my left hand. It’s really intricate, and though I can do designs on my right hand, I don’t think I can get that intricate.
I can definitely do designs though, and that is just a matter of practice and keeping your hand steady. My pinky is my savior, and I use it to prop up the rest of my left hand and give me some stability. I’ll also contort my right hand into some pretty strange positions to try to make painting the design easier. The muscle movement in my left hand is terrible compared to my right, so it needs to be as stable as possible. Leave your hand in the same position, and focus on just moving your fingers. Also, move your right hand to meet your left hand’s needs, not the other way around (if you can avoid it).
Also…breathe. Don’t hold your breath. Your back will hurt (at least mine does) because you’ll be working so hard to keep your body in control while you attempt the impossible.
Finally, let things dry completely. You’ll find that you’re very prone to smudging and really silly mistakes like that when you’re painting your non-dom hand. Letting everything dry at its own pace will reduce that risk.
Hope that helps!