It activates by repeatedly taking in and releasing prana (energy) from the forehead to the back of the head (and the throat, chest).

Like breathing, it first takes in prana, which is energy, from the forehead (as in yoga), and then draws it to the back of the head, and then to the throat, chest, and abdomen. It is taken in from the forehead, not the nose or mouth, but the sensation is similar to breathing. It is easier to synchronize the timing with breathing, so when you inhale, you take in prana from the forehead to the back of the head, throat, and chest. And when you exhale, you release prana from the back of the head through the forehead to the front. This is repeated.

At that time, especially the area around the back of the head is exposed to the flow of energy, and that area is activated.

It is like waves repeatedly washing over a slightly rocky beach, and like waves moving strongly between the rocks mixed in the sand, even if the rocks block the waves, the prana that enters from the forehead and then exits moves the hard parts in the head from the back to the front. It feels like the area around the hard parts in the head is being eroded and becoming softer, and that the loosening is gradually accelerating.

The obstacles in the head are not as hard as stones, but not as loose as sand, and have some flexibility like cartilage, so by repeatedly taking in prana from the forehead, they gradually loosen and relax.

This kind of method of taking in energy from the forehead is similar to descriptions in classical yoga and spiritual practices, and I think they have common points.

In classical yoga, there is a practice of repeatedly inhaling and exhaling prana through the third eye, Ajna chakra, located between the eyebrows, as a method to awaken it.

In the Theosophical or Brotherhood systems, there is a method of moving consciousness back and forth from the third eye to the back of the head. In that case, there are also descriptions of first taking in energy from the universe through the third eye and filling the whole body.

Although there are slight differences in words and expressions, I think they have the following points in common:

・Kundalini (the central energy channel of the spine)
・Ida and Pingala (the energy channels on the left and right sides of the body)
・The third eye, Ajna chakra, located between the eyebrows
・The back of the head is the key
・Sahasrara, the crown chakra, located at the top of the head

As it is said in spiritual teachings and among indigenous tribes, "it must reach the back of the head," and I think that is probably correct.

At my current stage, I haven't quite reached the back of my head, but rather, I've only reached it a little bit. However, I think the direction is correct.

In reality, this kind of technique is often mentioned in books, but until now, I haven't been able to practice it properly. Even when reading books, I often wondered if this was really all there was to it, but now I think that the necessary conditions were not met. If you are not prepared, you won't understand what you are reading, and nothing will happen. I think that is the case.