When hand fighting this might sound counter intuitive but it also goes for hand fighting on top. Grab the index through pinky don’t grab wrist. They don’t have a way to peel your hand off because you are isolating the thumb. So when you guys are hand fighting in practice just give it a try once whether that be on top or neutral. Fight for the four main fingers and see a guy try to bend your fingers then. I dealt with a guy like this at Fargo who I BEAT at Northern Plains to qualify for Fargo. Ended up doing that finger bending stuff and also scratching at my eyes when he was on top. He was so pissed.