Ds1 seems to be developing a physical tic. He stretches his mouth open very wide. He says it relaxes him. We tried to do a whole page of reading without doing it today "as an experiment" to find out if it was voluntary or not. It appears not to be. He's trying not to let it happen when his mouth is full (it's a bit disgusting then!) but generally it seems to happen when he's tired.
What do I do? Start recording when it happens? Sit on it for a bit in case it's to do with having dry lips or something?
When do I need to worry, basically?