i saw some ducks doing exactly what you were talking about! They were squawking at each other and then after they were done they went their own ways and both parties flapped their wings and shook their shoulders just like you demonstrated! Love it. It'd be a fun cultural shift to witness if we made this socially acceptable :) I think most folks are physically inhibited and forget to be silky, even in argument. When I am mad and about to direct it to my son, I like to exaggerate the physical expression of anger to take the weight off. It makes him laugh so it diffused my stress :)