What means ,,Nyappy'' ?

Nyappy is the "logo" of the band. Miku-san said that Nyappy was created like "Happy" and unnyappy is "Unhappy", but with time, last 년 (2009), they said it was used for everything (answering the phone, bye, hello, how are you, etc.)

What Miku is doing with the hand is the "nyappy"

NYAPPY means hello 또는 cool an cafe style