He bit down hard on the inside of his lower lip.

Then he looked up, bit his lower lip and began.

She looked up at him, and bit her lower lip.

She saw the fire in my eyes and bit down on her lower lip.

He bit down hard on his lower lip to make himself stop.

She bit her lower lip and looked away from him.

She bit her lower lip and looked away from him for the first time.

He bit his lower lip and tried to think of any good reason not to press it.

She bit her lower lip, then finally made herself look him in the eye.

She bit her lower lip as if to think it over.