Nice work with your Pea Coat.
As far as the death grip on the yoke....I've made students grip a pencil along with the yoke. Have them grip the pencil so it goes under their index and pinkie finger and over their middle and ring finger. Hopefully that made sense. They are pretty much forced to use their thumb, middle, and ring finger to control the aircraft. Also, the harder they grip the more it hurts. Which can be fun if they have a serious hold on the yoke.
Or, you could just break their ring and pinkie fingers.
Whatever you prefer.