I have watched my girls flip upside down on couches and hang over my lap. They have intentionally isolated themselves at times and craved our laps.
These forms of self-regulation are not limited to vulnerable children or even children. I do yoga as much as I can these days in attempt to regulate myself.
BUT... 4 years ago, they had very little idea how to regulate themselves and were dependent on us to help and protect them from over stimulation.
We would have meltdowns lasting multiple hours. Even when we knew they were safe, they did not "feel safe". Department stores, loud noises, strong scents, large family gatherings, meal times and parties are common triggers.
When you are caring for a vulnerable child or love a person who is highly sensitive (pronounced responses to stimuli regarding any of the 5 senses), helping them learn to avoid triggers and coping strategies will serve you well.
As a parent, my gut reaction is to have them sit down and be still, look everyone in the eye when they are talking, and stay in the middle of the party. This does not help them and will often lead to melt downs then or later and draw more attention than the coping behaviors.
More on self-regulation techniques
Excellent read to understand why self regulation is compromised in children who have endured trauma no matter their age.Caught Between the Amygdala and a Hard Place