one of my old TKD student dislocated my thumb while i was teaching him how.. he was too excited and did do low study pressure.. he simply jerked it down and i heard a CRACK.
i smiled at him told him not to do that again and had my brother teach him and lecture him and teach him not to jerk that he only does that in a fight not in class...
he was about 6 yrs old.. the kid was a green belt..
after that i went to the back to the adult gym area.. private room area no one was around then i was mumbled and was pissed.. from the pain,... my master had come in to "fix" it.