Tales from Duty Finder: Some make you laugh, some make you cry. Let's vent.

[Nicolepwned]

I just want to make sure. Pop the buff[s] once you've stopped at the place you want your mob to gather, not while you're running.
While you're running, unless you're lagging badly, you shouldn't be getting hurt too much. In case you do though, try to get hit in on everything as you're moving so that your healer will have some leeway to throw out a heal or Stoneskin mid-pull.

I typically wouldn't pop it while pulling if I was with a friend or somebody I know, because I trust them. But considering how DF healers are a crapshoot, I just pop it while pulling to mitigate some of the damage so there's less emergency-mode once everything is rounded up!