According to Osho, Tantra was a powerful, scientific path to transform sexual energy into enlightenment, but sex-repressive society violently persecuted tantrikas—massacring couples, burning scriptures, driving adepts into forests. To preserve the living stream of methods, masters chose "whispered transmission": pass it quietly, person-to-person, not publicly. In India, where many sages existed, martyrdom stirred little outrage, so secrecy became the only practical way to keep Tantra alive.
They whispered because open teaching got them killed, so they shared the wisdom quietly to keep it safe and alive.
From the Discourses
Passages where Osho speaks to this question — each links to the complete discourse.
Beloved Osho, why did the great masters of tantra call their teaching "the whispered transmission"?
The system of tantra is one of the most important things that has ever happened in the history of man. Everything else is secondary because tantra is an effort to transform living energy into its ultimate form, of enlightenment. But because the living energy is sexual, tantra became condemned -- condemned by the sex-repressive society, the sex-repressive religions. It became so condemned that tantrikas have suffered more than any other system of thinkers, philosophers, seekers. One Indian king, Vikramaditya, killed ten thousand couples. It was a special sect of tantrikas, really daring people. A man and a woman lived in one robe, naked. Inside they were naked -- just covered by one robe. They used to wear a blue robe, signifying that "because of the stupid society we have to wear something; otherwise the sky is our only robe" -- hence the blue color. Because of the blue color they…
Verse (Sanskrit): ओशो, काम-ऊर्जा को ध्यान व समाधि की दिशा में रूपांतरित करने की साधना में तंत्र का क्या-क्या योगदान है? कृपया इसकी रूप-रेखा प्रस्तुत करें। Transliteration: ośo, kāma-ūrjā ko dhyāna va samādhi kī diśā meṃ rūpāṃtarita karane kī sādhanā meṃ taṃtra kā kyā-kyā yogadāna hai? kṛpayā isakī rūpa-rekhā prastuta kareṃ| Translation: Osho, in the sadhana of transmuting sex-energy toward meditation and samadhi, what are Tantra’s contributions? Please present its outline. Tantra is nondual. It accepts the One alone. That which is called evil is also a form of that One. That which is called inauspicious is also a form of that One. In Tantra’s mind there is no condemnation of anyone—condemnation simply is not. G. N. M. Tyrrell has written a book: “Grades of Significance.” In the Tantric vision the differences in life are differences only in degrees of significance.
For example, you wrote from the West that you have met some Tantra experts, and they have said something to you and you are feeling confused. You have to understand many things. Those Tantra experts are all bookish. They have read about Tantra, they have read Tantra scriptures, but Tantra is not in the scriptures. It is a secret, esoteric teaching. Whatsoever is written in the books is a camouflage -- it is just to distract foolish people; it is not the truth. The truth is always delivered in an intimate, immediate contact between the master and the disciple. It is a transfer beyond scriptures, a transmission -- direct. Yes, scriptures are there, many scriptures, and great philosophy, but all rubbish! That is just to let the foolish people get occupied, that is not for the real seeker. It is for the student, but not for the disciple.
At the start of sexual union keep attentive on the fire in the beginning, and so continuing, avoid the embers in the end.
WHEN IN SUCH EMBRACE YOUR SENSES ARE SHAKEN AS LEAVES, ENTER THIS SHAKING. EVEN REMEMBERING UNION, WITHOUT THE EMBRACE, TRANSFORMATION. ON JOYOUSLY SEEING A LONG ABSENT FRIEND, PERMEATE THIS JOY. WHEN EATING OR DRINKING, BECOME THE TASTE OF FOOD OR DRINK, AND BE FILLED. Once you know this, even the partner is not needed. You can simply remember the act and enter into it. But first you must have the feeling. If you know the feeling, you can enter into the act without the partner. This is a little difficult, but it happens. And unless it happens, you go on being dependent, a dependency is created. For so many reasons it happens. If you have had the feeling, if you have known the moment when you were not there but only a vibrating energy had become one and there was a circle with the partner, in that moment there was…
Osho, please shed some light on this clear method of returning.
There are a few things to understand here as well. Ordinarily we have no idea that every touch of ours is a magnetic touch. When we touch someone filled with love, the one who is touched senses the difference. When we touch filled with hatred, that too is sensed. When we touch with indifference, even that is felt. In all three states our magnetic element flows in different currents. And if, with the whole mind and a firm resolve, one concentrates entirely in the hands, the magnetic currents become very intense—what Mesmer called magnetic passes. If we lay a person down naked, do not touch the body, and hold both our hands above the head at a distance of about four inches, keeping that gap, and then, while vibrating the hands strongly, move them the same four inches above the body down to the feet, and do this for fifteen…