Safety amongs beginners
I am new to aikido and have yet to test for my yellow belt. I have trained at other martial arts and know that the beginners are usually the most dangerous people on the mat.
One of the other beginners where I train really is a danger. I am frequently paired with hime while we practise our grading moves, I try to avoid practising with him at other times because I am worried that I am going to be seriously hurt. He does not seem to know his own strength despite me telling him several times a session and usually leaves marks from a wrist grab. More than once he had chopped off my circulation. He also seems to have no sense of balance and often finishes a throw by falling on me. I must point out he a a lot larger and heavier than I. Sensei is aware of the problem but there isn't a lot he can do beyond warning him to do things slowly and carefully.
I know this guy can't be the only person in the world like this and I'd like come advise. I don't want to stop him training or cause a scene but nor do I want to see someone get hurt