I went to special education classes in grade school, and the teachers there would pin me to the ground with my arms behind my back & kneel on top of me, put me in a padded blue box with no light for hours at a time, and also on occasion made me sit cross-legged in the corner with my arms behind my back while they sat on top of me.

It was not a particularly fun time, and it was very difficult to pay attention to work when other kids were going through the same thing.

There's other stuff from home-life & interactions with other people, but that's probably the most notable & persistent situation that I can remember.