1. The shakuhachi (しゃくはち) is a Japanese flute made out of a hollow length of, most frequently, bamboo, with five holes for fingering, creating musical notes based on the pentonic scale.

But the lovely, haunting sound produced by a master player of the the instrument is caused by blowing across a chamfered cut at the mouthpiece, called a fipple. Many beautiful tones may be coaxed out of such a flute, but extraordinary skill in use of the lips and tongue is necessary, as well as relaxation of of the throat muscles to widen the air passage is necessary.

It may be because of this great skill in applying lips and tongue to the mouthpiece, as well as the ability to widen the air column in the throat, that the second, slang, use of the word has come about.

2. "shakuhachi" (しゃくはち) is slang term in Japanese for fellatio.

Briefly, "the realization that each random passerby is living a life as vivid and complex as your own." Originally from the Dictionary of Obscure Sorrows, which has a lot more beautiful neologism definitions like this you might enjoy.

1) Traditional Japanese wooden flute.

2) Blowjob.

1. Traditional Japanese flute
2. Blowjob