The technique is called bigana brova. It involves lying down in an open field and looking into the sky. You are supposed to intensely focus on the limitless bluness luminosity of that vast space. In a moment, close your eyes and you will feel the absence of that vast blue space. But you are the awareness in which the vast blue space was appearing. Drop that too wil that still the mind. What happens then? You can't say. If you try to know what happens, then the mind will kick in again. So it's much better to keep short circuiting the mind once in a while.
Q&A session lead by Swami Sarvapriyananda at the Vedanta Society of New York on June 5th, 2022. List of questions with timestamps:
00:00 - Intro
01:32 - How is it that the self is in all beings from the chit (consciousness) perspective?
18:37 - Where is my consciousness when I am sleeping? Can I use sleep as a spiritual practice?
26:55 - Will a realized person retain their individuality after enlightenment?
40:38 - Why do we call this world false?
55:53 - What does Sri Ramakrishna mean by going into the black water (in reference to samadhi)?
01:00:30 - If we want to take up a life of renunciation, what practices should be followed?