He opened his mouth to speak again, then clamped it shut.

It was all she could do to keep her mouth clamped shut.

His mouth clamped shut suddenly as if he'd revealed something he hadn't meant to.

She opened her mouth to plead with him, then clamped it shut again.

West fell silent, his mouth clamped shut as if there were things he wanted to say, but couldn't.

His mouth clamped shut, as if he'd realized he made a mistake.

Now it was the General's turn to keep his mouth clamped shut.

No wonder everyone told us he kept his mouth clamped shut all the time.

Now, his mouth clamped into the grim line she was familiar with.

His mouth clamped shut in a tight line, and he didn't speak for some time.