My dog likes to nibble gently.

He nervously gave my hand a gentle bite.

He forced the dog to clamp the leash with its teeth.

He was slowly chewing the steak.

After failing, he blamed himself and was biting his own navel (figuratively expressing deep regret).

There is a proverb, 'a cornered rat will bite a cat,' which means that a person driven into a desperate situation will fight back even against an opponent they would normally fear.