This meditation is a fast, intense and thorough way to break old, ingrained patterns in the bodymind that keep one imprisoned in the past, and to experience the freedom, the witnessing, silence and peace that are hidden behind these prison walls.
The meditation is meant to be done in the early morning, when as Osho explains it, the whole of nature becomes alive, the night has gone, the sun is coming up and everything becomes conscious and alert.
"This is a meditation in which you have to be continuously alert, conscious, aware, whatsoever you do. The first step, breathing; the second step, catharsis; the third step, the mantra, 'Hoo.'
Remain a witness. Dont get lost. It is easy to get lost. While you are breathing you can forget; you can become one with the breathing so much that you can forget the witness. But then you miss the point. Breathe as fast, as deep as possible, bring your total energy to it, but still remain a witness. Observe what is happening as if you are just a spectator, as if the whole thing is happening to somebody else, as if the whole thing is happening in the body and the consciousness is just centered and looking. This witnessing has to be carried in all the three steps. And when everything stops, and in the fourth step you have become completely inactive, frozen, then this alertness will come to its peak." Osho