I am curious how other practitioners are taught. Often I see misunderstanding between the crescent and wheel kick. I am aware of two crescents; inside and outside. Often the outside is used as a spinning kick. Spinning or not the outside crescent strike is with the blade (outside) of the foot. I use the spinning crescent as a closer in kick always going to the outside of the body, over the shoulder to the ear or side of the face/jaw. From a fighting stance the reverse (back leg) crescent is a low percentage kick and it exposes your front side during the kick. However, if you are open stance to your opponent it can be effective. Front leg crescents are weak but can be effective blocking. Wheel kicks (always spinning) are great for the speedster. Very fast, very powerful, an accomplished kicker can hit the wheel faster than most people can throw a reverse kick. And can often kick through a front leg kick still being effective. Very good defensively as they create little opening when done correctly.