Maybe only women will understand this, but do you ever catch yourself with your mouth wide open while you're trying to apply mascara? And then if you try to close your mouth, if you concentrate on pressing your lips together, it's almost impossible to apply your mascara correctly? Chuck experiences the exact same thing when he tries to roll over. He can't do it without making a werewolf face, and I bet if I tried duct taping his mouth closed he'd be completely immobile.