Another grip break that works extremely well from the "middle finger" defense is the swimming grip break. Starting with the pocket grip, you actually want to make your pocket hand shallower for this one, so you allow room for your other arm to swim through. If your left hand is in your pocket, your right hand is going to swim under, but not from the side that feels most comfortable and natural; instead, you're going to swim through from the same direction your first hand is fed through. This will feel (in scientific terms) wonky, but it's going to pay off when you have the leverage to shoulder lock your partner and strip their grip along the palm that's trying to grab. Your left hand can now come free, and then clasp your right hand over the top, dropping your elbow down to help with the leverage. As you wrench their arm free, be careful not to inadvertently shoulder-lock your partner. If they straighten their arm to defend, you can finish the armlock with their arm trapped under your armpit.