Advice on mum?

My baby is 4 week old and my mum means well but she’s 100 miles an hour with everything. She tries to tell me what to do with him but I’ve already spoken to her about this and she apologised, she’s also a bit rough and ready with him… today was the final straw when she came round and ended up chucking him in the air once! My partner told her straight away “he’s too young!!” I could tell she was embarrassed about what she just did and tried to brush it off as she was “just changing position with him” I’m really annoyed, luckily he is absolutely okay! I know she doesn’t mean it but I’ve told her a million times he’s only little!! She says she knows what she’s doing as she had me and my brother…. How would you handle this??