Somehow he forced his lips to move, though they felt numb.

She forced her lips into a smile that felt brittle enough to break.

That was all he could force past his lips for the first several minutes.

He forced his lips into a smile and bowed lightly.

Looking as if he had to force his lips around it.

Try as she might, Adele wasn't able to force her lips into a smile.

She forced her lips into a smile, knowing it held no humor.

With an effort she managed to force her lips into a smile.

She smiled to herself, then forced her lips to uncurve.

Through sheer effort of will she forced her lips to move.