I believe the "Blue Pearl" bindu is mentioned in the Markandeya
Purana. MMY's book "The Play of Consciousness" was first called "The
Blue Pearl". M. describes out he was able to travel out of his body
riding the Blue Pearl.
Also, M. stated that the Blue Pearl offered him a Siddhi of
immediately discerning the "level" (meditation level in terms of
experience, Kundalini, etc) of persons who came before him.
Since I bowed directly before him on numerous occasions, I wonder
what his Blue Pearl told him. Probably not much!. (maybe it was
silent - that would be an interesting twist).
I also persuaded Charlie Lutes to visit Muktananda when the latter was
in Santa Monica; but I seriously doubt that Charlie would bow all the
way to the ground before M.