DD is a sensory seeker and stims a lot (hand flicking on smooth surfaces mostly, like any smooth surfaces she can find). The most recent behavior started as what we call her cheesy grin. When happy she would often tilt her head to the side pretty sharply and give us a big cheesy grin while making a sound (she doesn't talk).
It has developed into her tensing up her whole upper body to the point her hands and head shake. She is happy whenever she does it and is alert and usually has a wide open mouth. She appears to do it on purpose. Does this just sound like new sensory seeking behavior, another form of stimming, or something we should worry about?