Humming Bee Breathing also called Drone Breathing
A humming sound coming from within and vibrating in my head, makes me feel focused and concentrated.
I start by plugging both my ear-holes with the thumbs. Index fingers covering the eyebrows and rest of the fingers covering my eyes.
While the mouth is closed and teeth slightly apart, I inhale slowly through the nose, until my lungs are full.
Exhaling slowly while making the sound of the letter M ( or OM) resulting in a continuous, humming sound from the throat. The pitch of the sound can be high or low, whatever feels right. The sound should reverberate in the head and the vibrations felt as if in the center of the head. When air is expelled to almost the max, the frequency of the sound drops, a bit like a fading siren.
When unplugging my ears, I sometimes feel a cool sensation in the ears that lasts for a few seconds.