Think about "opening" your hand, fingers and thumb at release. Or, pushing your thumb nail against the back side of the hole. The key is to keep your thumb straight. If you drop the ball at this point, that's okay, mission mostly accomplished. Add some tape to the thumb hole.
I would have your fit checked also, but don't necessarily think more reverse is the answer. That could just let you "knuckle" the ball more AND get out of it faster. There could be other reasons that you are knuckling the ball. Span too short, too much reverse pitch, too much bevel, thumb hole too big, and infinite combos of these.
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