Since spinning is mentioned a fair bit here I once had a tricky situation spinning an RAE Bedford Auster AOP 9. It has of course a side by side cockpit and a young boffin wanted to be shown some spins.
As I tried to recover from the first one (pattering away as one does) I found the stick was jammed fully aft. Then I looked about me and realised my pax had his eyes shut and was pulling hard back with both hands on the stick. Since height was limited I smacked him hard across the face and he let go. Tricky in a tandem cockpit.