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Recently when playing I have noticed myself sniffing while breathing and was curious on how to fix this and what may be causing this sniffing

Are you exclusively nose breathing or is it mouth and nose? How long have you been playing?

I sniff breathe all the time to get through certain passages. Two of my main teachers, Tommy Johnson and Roger Bobo, highly encouraged this. Exclusive nose breathing isn't great for tuba playing, but it's a great tool in addition to correct breathing. Best wishes.

The way you describe it makes it sound involuntary, I suspect you are trying to fit too many measures in between breaths. Try forcing yourself to breathe through your mouth every couple of measures, or go through whatever piece you are working on without the tuba and just inhale and exhale though the piece.