Check out this trick shot you can play from your knees when your ball is close to the bunker lip and it’s hard for you to balance yourself. I haven’t tried this but it does “seem” like a good sand trick shot.
Your knees and shins give you plenty of ground support, so don’t be afraid to make an aggressive swing (flare both feet out for an even wider base). Keep your rear end and your back straight, and try to hold this position as you swing the club back and through. Don’t pick the club up — get your shoulders moving as well as your arms.
The biggest mistake you can make is bending over too much. That makes it easy to lose your balance. Use your butt as ballast to keep your posture tall and your swing in control.