Kip Puterbaugh with a nice video on how to hit the stinger.
I like this shot because I think the thing that made Tiger such a great iron player and a winner even when his driving was abysmal at times, was his ability to hit the ball in all different windows. Somebody like Mickelson pretty much hits it on one window...high. I think that's part of the reason why Phil likes to bomb and gouge so much, he doesn't feel comfortable working the different window trajectories, so take it out of play by bombing and gougin.
This is a great shot for golfers to practice IMO because if you can do this, you can likely hit full swings all day. Most PGA Tour pros could hit this shot pretty easily, but watch a good amateur and maybe 40% can do it.
The choking up on the club reduces the clubhead speed which reduces the spin and keeps the trajectory lower. The only other thing I could recommend, besides practicing the shot first, is to go S-L-O-W because the golfer's tendency is to rush and then they get out of sequence in the downswing.