I too shake a lot and scratch at my arms but like Starry Night my t holds my hands or arms to stop me. I have also done it as a form of sh at home and have scars from it so she tends to encourage me to use a different way to express myself. If I'm not doing it too bad she will try and ignore it but she says she won't let me hurt myself properly in the room. Maybe yours is trying the ignoring hoping you will stop?