He's been doing this all morning. He's inside the house, so I know he's not cold. Otherwise he's acting normally - happy and running around. When he lays down he doesn't do it, but when I talk to him or pay attention to him, he gets excited and he starts chattering his teeth again. His tail is wagging the whole time, so it doesn't seem to bother him. Has anybody else experienced this? Any ideas of what's going on? As a side note, I just started a new job in another city, so I've been away from home during the week for the last two weeks. My husband says he's been very clingy while I'm gone, and when I'm home he's clingy to me. Could he be stressed? Should I do something?