[freddystone]

If you don't want her to play rough, don't let her play. The other dog will let her know when she's getting too rough for them. I let mine wrestle to their heart's content. Just keep an eye on body language and make sure it's not going to escalate. If you're unsure of the body language, break it up and make them take a break, or just don't let her play with other dogs.
I only let my two play together. Not a big fan of letting them play with other people's dogs. I don't trust other dogs, and I don't trust other people.

+2. I have had a couple of incidents where ignorant owners have totally misjudged the escalation in their dogs behaviour & I had to get some ginger up them before things turned nasty.
In my (limited) experience Bull Terriers playing together do not look like they are playing, really rough. With other dogs it's still rough ( you need big ones, little ones get broken ) but other breeds don't seem to engage as much, run, play wrestle, run some more, rather then Sumo.
If in doubt call time immediately & calm the dogs