I think it is just a yorkie trait. It is funny at dog shows, an exhibitor can brush their yorkie out really pretty before putting him on the floor and moving him for the judge. It never fails that as soon as the yorkie starts to move they will have to stop and shake. Its like they feel they have to fix their hair the way they like it.
Another cute yorkie trait is the yorkie stretch. My Dixie will bark at me to pick her up but so many times she will just back up and do this silly body stretch before stepping forward to be picked up. I am sitting there there thinking, 'okay, anytime you are ready'
