Finding the sweet spot for finishing the Inverted Armbar is a Goldilocks problem: When you strike his arm with your elbow pushing down, you are powerful but lack the control to readjust when he tries to escape by turning. If you grab with your hands to try to push his elbow down, you have great control but very little power. The best way is the middle between the two extremes; strike his elbow as if your were arm-wrestling and contact with your forearm. This will allow the room to steer his elbow back to danger when he tries to twist his arm free. Marcelo uses the Seatbelt Grip, hand-over-hand, to apply pressure because other grips have the tendency to help the opponent pull himself close to you by grabbing onto your head for an escape. The Seatbelt-style grip avoids this and assists in the finish by allowing you to drop your bodyweight into the armbar.