SD Stretch Muffler is a Kick Blow Counter used by Shouryu in the SD Hiryu and Vitual Hiryu Mode of Flying Dragon. In Flying Dragon, Shouryu only has one blow counter, which is in fact this move. However, in SD Hiryu no Ken Densetsu, he has two, the new one, which is seen as once the puch counter is executed the opponent is pushed back, and also this new move was very weak, and hardly used.
SD Stretch Muffler is performed by pressing "Left+K while guarding." It is shown with Shouryu catching hold of the opponent's leg as the opponent attempts a Roundhouse Kick. Shouryu then turns his back to the opponent and drapes the opponents leg over his neck, getting his opponent in an Argentine Leglock Hold, then Shouryu (still holding the oppoonent's leg spins around 540°, and throws the opponent across the stage.
In Professional Wrestlng, this move would be describes as a "Stretch Muffler Leg Whip", or a "Argentine Leglock Leg Whip".
SD Stretch Muffler should not be used often, as it is not very strong, as well as being very difficult to tell when the opponent will use a kick, especially when fighting a new character that you have never fought before.