Sex (Tantra)

[Tantra is dyadic yoga, White Tantra without sex, Red Tantra with sex (called Sexual Kung Fu in China). Black Tantra is anal sex.. The main secret is semen retention, from not at all as practiced by Mantak Chia, to the once in 10 sessions (less as you get older) recommended in The Toa of Loving.  Kept secret for thousand of years, it's one reason why there is friction between couples--the man realises he is losing energy so cuts down on sex, while the woman feels she is gaining something so wants more.]

See: Sex  Sex (anal) Porn Monogamy & polygamy

Healing with Sexual Energy – 6-part overview article, also in Nexus Magazine April & June 2007

Quotes
Much of the alchemical literature of Europe now appears to be a coded tradition of drug-and-sex programming.....This code is especially notable in The Chemical Marriage of Christian Rosycross (1615), which forms the visible link between traditional alchemy and modern Rosicrucianism. The mystical rose and cross from which the Rosicrurians take their name are, in fact, no more or less than the vagina and the penis, respectively...(For the curious, here is the rest of the traditional symbolism, as given by Louis T. Culling in his Manual of Sex Magich Cucurbit—the vagina; retort—the same, during copulation; eagle—the vagina, or the female mouth, depending on the context; lion—the penis; transmutation—the sexual "peak experience"; elixer of life—the semen; quintessence—the semen as transmuted by ritual and ecstasy.) ----Sex and Drugs by Robert Anton Wilson p66

Anal intercourse is the Tantric equivalent of such Hatha Yoga practices as Mulabandha (anal sphincter lock), and Asvini Mudra alternating relaxation and contraction of the anus).
    The secret tradition of magical Tantra teaches that the anus is an ultrasensitive erogenic and psychic zone directly linked the Muladhara, the basal Chakra. Hidden within Muladhara, Boiled and compressed like a spring, lies the primal power of the nervous system manifest as the Snake Goddess, Kundalini.
    The terminus for the "pipe of flesh" is the anus, composed of an internal anal external sphincter, rings of muscle surrounding a body orifice. The word "sphincter" means a "knot" or a "band" and is derived from the same Greek base as "Sphinx," the mythological beast epitomizing occult mysteries. The master of Tantric sex magic opens the anal sphincters of his Shakti, thus solving the riddle of the Sphinx.
    Anal intercourse is a specific Kundalini arousal method. Reference to Gray's Anatomy reveals the existance of an irregular, oval-shaped gland between the rectal wall and the tip of the tailbone, or coccyx, called the "coccygeal body.'' Although the function of this gland is unknown to
    Western physiologists, it is established in Tantra as the "Kundalini gland." Yoga has devised a wide variety of techniques to irritate and awaken this gland into activity, including Mula Bandha, Asvini Mudra, Tada Mudra (knocking the buttocks upon the ground, sending rhythmic shock waves rippling up the spine), and rolling on a cotton ball placed under the tip of the tailbone.
    Tantric activation of the gland is direct and swift through the dilation of the anal sphincters, with a consequent reflex effect upon the two branches of the autonomic nervous system. These two branches, terminating in the anus and rectum, are the parasympathetic (Ida, or braking influence) and the sympathetic (Pingala, or accelerating influence). As well as altering the state of the involuntary nervous system, anal intercourse, according to traditional belief, results in the ejaculation of semen into the rectum, which nourishes the "Kundalini gland" much as the white of an egg feeds the fertilized yolk or embryo. The Tantrist, sustain­ing his Shakti or Goddess with anal intercourse, facilitates the arousal of her internal fire.
    The Occidental mentality is conditioned to look upon the anus as unclean. The Hindu, on the other hand, is scrupulous in hygiene at both ends of the "pipe of flesh," having a firm tradition of rinsing the anus after bowel activity, using copious quantities of water and the left hand (the right hand being reserved for handling food when eat­ing!). Certain schools of Hatha Yoga consider washing the bowel daily with water through a system of natural enemas (Basti) as much a necessity as cleaning the mouth and teeth. Tantric practices may be viewed by some as "pervert" or "deviate," and in terms of the inner meaning of words, they are. "Pervert" means "to overthrow," "to turn around," while "deviate" (de and via, the way or path) suggests  "off the road," "out of the way." (Ecstasy through Tantra by Dr. Jonn Mumford p61)

Books
Energy-Karezza: How to make every wife sexually wild about her husband: Fascinating and powerful sex for marital fidelity and bliss by Stanley S. Bass