Never before have I heard "reach into an animal and grab its lungs from the inside" as a defense strategy. That's a new one.

As poorly conceived as it sounds. It’s not wrong. It’s the same advice for grizzly bears. You need to straight up break the animals instincts from attack to protect, and a non-armed way to go that is to attack eyes or mouth and eyes are hard to go to. Bears specifically have strong gag reflexes, IDK about dogs.