Back 2 secs, forward+kick. Ahh, the rushing elbow. Another useful move, but do not overuse it. Sooner or later your opponent will parry your attack and punish you. Try doing a MP Stungun Headbutt after this move.. it's almost inescapable even if blocked. If you connect with the elbow, always 2-in-1 into the Boomerang Raid. You can also run under jump-in enemies and screw up their timing/position.