I like the idea of the Cavalier all-out guffawing, but your animation isn't quite as effective as it could be. When we laugh, there's variation from person to person but it usually involves pushing the air out of our lungs in short, powerful little bursts, creating the "HA!" sound. This affects the entire body, especially the chest and stomach - ever notice how a fat person's tummy jiggles when they laugh? So I would try putting the motion in his chest, stomach and shoulders, not his head.