I could see his mouth twist as he tried to decide what to say.
He said the last with a bitter little twist of his mouth.
There was a harsh twist of his mouth, less than a smile.
He drank the wine with a twist of his mouth.
She just laughed, eyes and the twist of her mouth clearly skeptical.
He backed off with a satisfied twist of his mouth.
And after a moment, he smiled as well, the crooked twist of his mouth.
The twist of his mouth suggested regret rather than anger.
He made his mouth twist into the shape humans used to show amusement.
"You love me," he repeated, the words sounding all wrong on the twist of his mouth.