Just do it really lightly all around and check it. If it still rubs, do it lightly again and check it again. Keep doing this until you have sufficient clearence. Don't try to do it too fast otherwise you'll end up ruining it.

Oh, and I don't think you should "roll" it, just press it out a little all around the top part of each fender. Don't apply too much pressure to just one spot -- spread it out. I'd also jack the car up a little just so you have more room.