The flop shot is very valuable when you need to carry the ball over undesirable areas such as water and sand from about 10 to 40 yards. Hit properly the ball will land on the green and stop reasonably fast.
For best results a sand wedge is the proper club to use. Most high handicap golfers do not realize how often the pros use a sand wedge for other shots than sand shots. The club head has more loft and a bigger flange, both of which can get the ball higher with more backspin.
When executing the shot let the arms swing slowly and relaxed letting the club head do most of the work. Be sure and keep the arms moving through the shot and to the finish. The body moves with the arms but this is one shot where there is more feel in the arms than the body. The club head will slide under the ball. Do not try this shot off hard ground and tight lies.
Because the swing is so slow and relaxed with a big hinge in the wrists the club goes back farther than you might imagine. This shot requires a very slow rhythmic tempo while you keep your arms and center moving through the ball.