This is what i do - have one arm on baby's back to support their body, and the other ready to break their attachment if needed. If baby starts to pull away, i can push them towards my breast first (so less stretching of the breast), and then break the attachment before baby moves his head taking breast with it. I know when he is more likely to be distracted, and at these times i am more vigilant.

It doesn't really stop him doing it, but it does stop me from getting boob damage. A funky necklace he can grab seems to be the best way of keeping his attention on the job, and i know this will pass.