I run a front brake for those just in case moments. Most of the time though, I just slow myself using my legs, little whip skids, or little hop skids.
I rarely use it, but for those times when you really need it, damn, is it nice to have it there. I have one of the little Paul E-Levers, just a little one-finger lever that still gives me enough pull force to stop quick when I need to.