Last summer, during the British Open, Phil Rodgers taught me a unique sand shot, one that I did not have to use, I hasten to add, when I beat Phil for the championship in the final round. The situation occurs when the ball is in the sand very near the back bank of the bunker, and the bunker wall is so steep that you cannot draw the club back in the normal fashion.
I tried this shot a hundred different ways before Rodgers solved it for me. There is no problem setting your feet, so assume your normal trap-shot stance. Now just pick the club straight up, breaking your arms just as you would if you were picking up an ax to chop a piece of wood. Then hit down about two inches behind the ball with some extremely strong right-hand action. There cannot be any follow-through at all, because the club head must bury itself in the sand. The arc of the shot is up and down, not back and forth. You may look like a woodcutter, but the result is gratifying.