Butterfly Sweep when Opponent Attempt to Post to Defend (Intermediate)

Professor Lucas Lepri teaches how to sweep the opponent using the butterfly guard when they attempt to defend. Lucas has the butterfly guard and the opponent has both arms on the side with the elbows touching the mat. Lucas grips the belt on one side to prevent the opponent from posting on that side. As Lucas pushes the opponent away and sits up, the opponent posts out with his free hand. Lucas immediately under hooks that arm and sweeps the opponent to the opposite side, landing on the mount position.