Another important aspect to winning the battle for upper body control is blocking shoulder pressure via establishing a block with your arm. It looks a lot like the Maneki Neko cat you see at some Japanese restaurants. Your inside hand pummels inside of your partner’s arm and slides down to the biceps, then they swim their arm inside of yours to establish their shoulder pressure. When you do this drill, you will find you have to do all sorts of tiny elbow and arm angling to win the tiny micro game which pops up.
In this drill, the top player initiates the action by reaching across their partner’s neck to establish shoulder pressure on the neck. The bottom player responds by sliding their hand inside of the top player’s biceps, breaking the connection. If need be, the bottom player can use small, off-balancing movements to open this space up enough to insert their hand. Once the hand creeps in, you can turn your hand to hook your partner’s biceps.