Marcelo stresses several key aspects of the Hook Sweep from Butterfly Guard with Collar and Elbow Control: (a) Begin moving your hips for the sweep as soon as you smack on the Collar & Elbow; the opponent will more than likely slip out of your control if you wait any longer. (b) Elevate his hips with your hook vertically, and only turn over after directing his course to the mat for the sweep. (c) If he posts, and doesn't slip out after posting, push his elbow in toward his chest with your palm and finish the sweep. Drilling this particular technique may require playing with the speed, until the movement becomes automatic and more realistic.