It occurred to me to have crouching now, implies the old stop drop and roll tactic while ablaze(minus on a lava tile or engulfed).
So if on fire and not in lava/engulfed in flame(as in burning building). You could crouch and move from the tile you are on to 1 tile over(any direction) and back to that previous tile. Repeating this until you are no longer on fire, would simulate the Stop, Drop and Roll technique. No skill required. However maybe a slight faster dousing of the flame if you have traits that make you physically faster(or high Dex).
Not sure if jumping in a river/pond/lake helps. Have never been on fire where I would survive it.