The Yelp and Withdraw

When a bite is too hard, give one short, high-pitched "ow" and let your hand go completely limp. Do not yank it back — a fast-moving hand triggers a chase reflex and the puppy clamps down harder.

Then raise the bar over time. At first, react only to the hardest bites. Once those fade, start reacting to medium ones. Later, any tooth pressure at all ends the game.