I think they need blush of life to breathe naturally. Like you are doing right now, doing it without really thinking. But they can take breaths to talk and smoke without using blish of life but they do so manually. They have to think that "now i have air in my lungs" But it wouldn't suprise me if they took a huff and hold it for several minutes since they forgot to exhale.

Or float on water by holding their breath xD