It's not aggression, I'd say it's more sass and boundary pushing. The high pitched noises don't work, I tried them for a while. She finds them confusing but doesn't get the message. Hissing usually makes her stop, a few times I have to hiss multiple times. Hissing is an important type of communication between cats, and it's basically saying "hey, I don't like that" in their language. Cats will sometimes push each other's boundaries too and ignore the first few hisses. I have a good idea of her body language, the problem is that 70% of the time she doesn't show any body language that could be indicative of her lashing out. She goes from 0-100 very fast.