A small female helicopter instructor colleague once had someone freak out on a trial lesson and start grabbing wildly at all the controls, which in an R22 wouldn't be at all nice.
She said she ordered him to sit on his hands and not move, and apparently it worked for long enough for her to get straight back to the airfield...luckily in a helicoter you can land pretty fast if you need to. I thought about that when I had my first - and so far only - student who was utterly terrified on a trial lesson and wanted to get on the ground ASAP. Luckily all he did was sit there with his eyes closed while I uttered soothing words and got us down. It was the first time I'd really thought about how dangerous this job can be. After that I got a karate expert friend to show me some pressure point stuff. Not sure there's room in an R22, and not sure I remember it properly, but better than nothing...though hope I never need it.