Bhramari

Inspiration when rapid making sound like that of a large black bee and expiration very slowly making the sound as of a female black bee, to the superior Yogi, the use of this technique causes an indescribable joy in his being.

द्वितीयोपदेशः Chapter 2.68

अथ भ्रामरी वेगाद् घोषं पूरकं भृंगनादं भृंगीनादं रेचक मंदमंदम् । 
योगींद्राणामेवमभ्यासयोगाच्चित्ते जाता काचिदानंदलीला ॥ २.६८ ।।