Reddit reviews Taoist Yoga: Alchemy & Immortality

He is most likely referring to spiritual alchemy which isn't about the physical transmutation of matter as is generally associated with the word, but the transmutation of the self. A few things to read up on if you want to get into it are Carl Jung's writings on Alchemy, the esoteric branches of Taoism (Taoist Internal Alchemy), and this Terence Mckenna lecture in particular is fairly good primer on the subject. It all gets weird and is probably just a bunch of bullshit but is fun to try and wrap your head around if you're into that sort of thing.

The idea is that sperm contains the life essence, Essia, which is partially what's known as jing in Daoism or in Chinese medicine. This essence, if wasted through indulgence in sense-impressions, lustful thoughts, and ultimately through ejaculation itself, which seals the loss of the essence, will not be able to be converted into energy (chi) that your body needs to open its energetic channels.

Without an abundant chi and opening the channels, energy is obstructed to flow fully and cannot complete its process in its conversion to shen (spirit) allowing the kundalini to rise on its own. This is truly the basics of internal alchemy. I suggest the book Taoist Yoga if you wish to learn more in detail. Very high level information. These things aren't something that needs to be done purposefully or forcefully but will arise on their own with right practice.

This is somewhat of an oversimplification, but the general thing still stands. The sexual essence is a primary expressive fuel of your Great Work. If you continue to engage in sexual intercourse or lustful thoughts while continuing with internal alchemical exercises, you may hurt your kidneys and your kidney energy can get terribly low. Most people cannot feel this at all because they're completely out of touch with their bodies and the energy within.

Google up "Nei Kung" and read this book for an introduction to the martial arts aspects. There are also a couple of mediation books translated by Charles Luk which relate to the Toaist philosophical context. Also, Wilhelm Riech has some interesting theories - not to mention his life is an example of Western bias against the subject. For Indian as opposed to Chinese, look up kundalini meditation.

For occult sources, the OP already metioned a couple, plus there are the obvious mentions for Aleister Crowley in the blog post.

Currently I am studying The Secrect of the Golden Flower which I found an excellent copy of at my local bookstore. Once you go through this and get the gist of what the practice entails you'll find all sorts of interesting findings in neuroscience as well.

Ebryonic breathing/meditation

Small circulation breathing/meditation

Taoist yoga

Taoist Yoga: Alchemy and Immortality
https://www.amazon.com/Taoist-Yoga-Kuan-Charles-Luk/dp/0877280673

Internal Elixir Cultivation: The Nature of Daoist Meditation
https://www.amazon.com/Internal-Elixir-Cultivation-Nature-Meditation/dp/1943155135/ref=sr_1_2?s=books&ie=UTF8&qid=1478006245&sr=1-2&keywords=internal+elixir+cultivation

Healing Light of the Tao: Foundational Practices to Awaken Chi Energy
https://www.amazon.com/gp/product/1594771138/ref=pd_sim_14_3?ie=UTF8&psc=1&refRID=2P7K1FW99QSDG12HVPZA

Foundations of Internal Alchemy: The Taoist Practice of Neidan
https://www.amazon.com/gp/product/0984308253/ref=pd_sim_14_2?ie=UTF8&psc=1&refRID=5KF0N4TFRQQQ4PCVCH6F

The Tao of Meditation: Way to Enlightenment
https://www.amazon.com/gp/product/0804814651/ref=pd_sim_14_25?ie=UTF8&psc=1&refRID=5KF0N4TFRQQQ4PCVCH6F