pranayama classical
Sitting, you breathe in normally and then hum on the whole way out — a low, continuous bee-sound, lips closed, jaw loose — often with the ears lightly covered so the hum arrives from inside rather than outside. Repeat for a handful of rounds. Two things happen at once, and the tradition names both: the exhale becomes long and even without you counting it, and attention has somewhere unmistakable to sit. Set down in the Haṭha Yoga Pradīpikā (2.68), which describes the practice as drawing awareness inward toward subtler sound.