I had two dogs years ago that once in awhile their play would turn too rough and they'd get into it. Just hollering at them usually broke it up.
Now with Lacey and Mandy, it's usually Mandy that goes off on Lacey, probably because she's so spoiled (because she's sick) and possibly because she's not fixed. I have to pull Mandy off Lacey. I just grab her back legs and pull. Lacey doesn't seem to want to fight ,only defend herself, so she backs off once I intervene.It's not an everyday thing but it does happen.
Anyways I don't tolerate anything that seems to be too rough.I would say you be the judge, if it seems too rough break it up.