According to Osho, while separating the subtle and gross bodies is generally safe, there is real danger if the physical body is weak or damaged: once contact is withdrawn, parts may begin to disintegrate, making reunion difficult or impossible. Hence Hatha Yoga disciplines the body to prevent disorder, and deliberate, skillful separation enables easy rejoining—whereas accidental separations are riskier.
If your body isn’t strong, pulling your “energy body” out can make the body start falling apart, so getting back in may fail—so do it carefully and on purpose.
From the Discourses
Passages where Osho speaks to this question — each links to the complete discourse.
Is it possible that for some people who have been trying to separate these two bodies, then these two bodies cannot be reunited?
Yes, there is this danger sometimes. There is sometimes this danger. And many times it can happen that in this attempt they cannot be joined back. But generally, generally, such a danger is not there. In some conditions this situation can arise: if the body is in such a state that some of its parts have been completely ruined or can no longer function, and the moment the contact is withdrawn they begin to disintegrate, then rejoining will be difficult. And that is why Hatha Yoga has laid so much emphasis on the body. The effort to discipline the body wholly and completely was precisely so that, when the other body separates, there is no fear of the body becoming disordered. Then there is no obstacle to rejoining. And one who separates the bodies knowingly—who very consciously separates that body from this body—does not face much difficulty. Because the very…
Once the subtle body is out, it can't enter back into the physical body completely. The adjustment and harmony between the two is disrupted forever. This is the reason why the yogis have always been ill and have been dying at an early age. How can we prepare ourselves so that the disharmony may be avoided? Can the possibilities of illness be minimized? How is this possible?
In this respect too, the first thing is: the moment the subtle body goes out of the physical body, nature's order is bound to be disrupted. The phenomenon is not natural; one should say, it is beyond nature. When a phenomenon occurs which is contrary to nature, or which is beyond nature, the entire harmony and adjustment of nature becomes disorderly. A great deal of preparation is needed if one wants to save oneself from such a disorderly state. Various yogasanas and mudras, yoga postures, are very helpful in this respect. In fact all the techniques of Hatha Yoga are useful in this direction. So you need an extraordinary body -- an ordinary body won't work. You need your body to be made of steel so that it can withstand an unnatural phenomenon of such great magnitude. For example, there was no fundamental difference between the body of Ramamurti and…
Osho, once the tejas body goes out, it never quite re-enters fully and the harmony between the two is disturbed. Therefore yogis have always been sickly and have died young. What preparations are necessary so that disharmony does not arise? Can the chances of illness be reduced? How is this possible?
There are many such “unnatural” trainings. If the body has passed through them, it becomes able to endure that unnatural event; then the body is not harmed. But ordinarily these preparations take years. Later, raja yoga concluded: Why bother to save so much life? It takes twenty or thirty years—thirty at the least. If someone begins at fifteen, he will be ready around fifty. Raja yoga decided: Why be so concerned with the body? If the state is attained and the body falls away, what is there to preserve? So those preparations were dropped. That is why Shankaracharya died at thirty-three. Such a great event occurred, but the body was not prepared for it. Yet there was no need to prepare it either. Only if one sees a need should it be done; otherwise, there is no reason. And if you must labor for thirty-five years just to save thirty-five…
I was still in the tree, but the body had fallen below. It's difficult to say how I felt at that time. I was still sitting in the tree and the body was below. Only a single silver cord connected me with the navel of my body -- a very shiny silver cord. What would happen next was beyond my comprehension. How would I return to my body? I don't know how long this state lasted, but it was an exceptional experience. For the first time I saw my body from outside, and from that very day on the body ceased to exist. Since then I am finished with death, because I came to see another body different from this one -- I came to experience the subtle body. It's difficult to say how long this experience lasted.