According to Daoist immortal, Lu Dongbin, “the Golden Flower is the light. What color is the light? One uses the golden Flower as a symbol. It is the true energy of the transcendent great One.
The Golden Flower is the Elixir of Life (Jin Dan). All changes of spiritual consciousness depend upon the heart. There is a secret charm which, although it works very accurately, is yet so fluid that it needs extreme intelligence and clarity, and the most complete absorption and tranquility. People without this highest degree of intelligence and understanding do not find the way to apply the charm; people without this utmost capacity for absorption and tranquility cannot keep fast hold of it.**
The work on the circulation of the light depends entirely on the backward-flowing movement, so that the thoughts are gathered together. The heavenly heart lies between sun and moon.
Since when has the expression ‘circulation of the light’ been revealed? It was revealed by the ‘True men of the Beginning of Form’ – Guan Yin-shi. (The one for whom legend said that Laozi wrote the Tao Te Ching.) When the light is made to move in a circle, all the energies of heaven and earth, of the light and the dark, are crystallized. That is what is termed seed-like thinking, or purification of the energy, or purification of the idea. When one begins to apply this magic it is as if, in the middle of being, there were non-being. When in the course of time the work is completed, and beyond the body there is a body, it is as if, in the middle of non-being, there were being.
The radiation and dissipation of spiritual consciousness is chiefly brought about by this energy when it is directed outward. Therefore the Way of the Golden Flower depends wholly on the backward-flowing method.” [The Secret of the Golden Flower – W/B]
The above extracts about summarized the gist of what a neidan practitioner needs to do to see the Golden Flower. To circulate the light, he or she has to use the backward flow method. After a lengthy continuous practice, the energies of heaven and earth, of the light and the dark will crystallized to form the Golden Flower. Later in the middle of being, there will be non-being, and when the work is completed, that is attaining Tao, in the middle of non-being, there were being.
If your neidan practice differs much from the Way of the Golden Flower, you may not see the various signposts indicated by the ancients – Laozi and Buddha - and the Quanzhen Daoist immortals in their classics and texts. Whatever method you are using, if during meditation you do not feel the heat and see the light, your neidan practice can be said to be incorrect. Good luck.
This is a higher level of the right person for Tao, perhaps applicable to the neidan adept. Sages will have already reached the level of extreme intelligence and clarity to fathom human nature and humanity. Whether they had the most complete absorption and tranquility to keep hold of it is another thing, altogether. Perhaps their absorption is most complete but without the necessary cultivation of virtues to rectify the heart could they reached the utmost tranquility to hold on to the secret charm until completion?