There are frequent times that I am aware that I am no longer just breathing air. These are the times that the rush of air in and out of my nostrils continues, but there is more. My chest expands and contracts, but I no longer feel the rising and falling. My awareness shifts from the fundamental sensations to a focus on my breathing as known.
I become conscious of the awareness of my breathing. My whole body lets go of sensation as I become conscious that sensation is known. I become absorbed, not in breathing, but in the awareness of my breathing.
Breathing becomes a different kind of experience. I am aware that I am breathing air, but my actual sensation of breathing fades away. I might as well be breathing water because my consciousness has shifted to an experience of something other than air. I am breathing something else.
What I am conscious of is more like an inhalation and exhalation of the fabric of the universe. I feel afloat in a vast ocean and I am breathing in that ocean and becoming part of it. The experience has shifted from the sphere of my senses to the conscious reach of my mind. My mind is at rest as it floats on an ocean of awareness and becomes aware that I am part of it.
I have been breathing air all my life, since that first moment when my lungs expanded. Now it is my mind that expands, and I breathe in the vast ocean of the sphere of everything.