The user turns back for a brief second and does a leaping back-spin kick forward. This move has good range, and can hit some aerial foes (at certain angles) as a sold stuffing-poke. When blocked however, the kicking animation is increased slightly and leaves the user vulnerable to counter-attack (or an Alpha Counter if timed right). The move is often considered an "approach", or move that helps Charlie/Guile attack foes directly, as well as to bait out low attacks.
In Street Fighter Alpha 3, the move can be used going forwards or backwards, interestingly, as opposed to just forward or stationary, which allows for some gimmicks.