First it must be said that the breathing/blowing that you need for woodwind instruments is quite unnatural.Naturally breathing means breathing through the nose, which humidifys and warms the air and filters all kind of dust, so it protects your lungs.Playing the clarinet you will breath through your mouth.Natural breathing means slowly filling the lungs - but not absolutely full, rather a third or so - and then slowly releasing. When playing a wind instrument like a clarinet - and much more a bass clarinet - you will often have no time for breathing in - but still must fill your lungs to the extreme.