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

Just like breathing, first, take in prana, which is energy, or what is commonly called an aura, from the forehead (as in yoga), and draw 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, take in prana from the forehead to the back of the head, throat, and chest. And when you exhale, release prana from the back of the head through the forehead to the front. Then, repeat this process.

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 and receding on a slightly rocky beach, and like waves moving strongly between rocks that obstruct the waves, the prana that enters from the forehead and then exits moves the hard parts in the head back and forth. It feels like the area around the hard parts in the head is being eroded, becoming softer, and the loosening is gradually accelerating.

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

This 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 ajna chakra (between the eyebrows) as a way to awaken it.

In theosophical or brotherhood systems, there is a method of moving consciousness back and forth from the forehead to the back of the head. In some cases, it is described as first taking in cosmic energy from the forehead and filling the entire body.

Although there are slight differences in words and expressions, I think the following points are 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, between the eyebrows
- The back of the head is the key
- Sahasrara, the crown chakra, at the top of the head

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

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

In fact, this kind of method is often described 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 will not understand what is being said, and nothing will happen.