'returning the semen/essence to replenish the brain' or coitus reservatus) is a Daoist sexual practice and yangsheng ("nourishing life") method aimed at maintaining arousal for an extended plateau phase while avoiding orgasm.

In traditional Chinese medical theory, the shen (腎, "kidney") organ system was considered the reservoir for semen, bone marrow, brain matter, and other bodily fluids.

In Taoist sexuality or sexology manuals, this process is regularly described as follows: jing (the seed, raw and dense) is transformed into chi (vital energy, subtle and circulating).

Bǔ (補) has equivalents of: (1) "mend or patch clothing", (2) "repair, restore; remedy, redress; improve, ameliorate", (3) "add to, supplement; supplete, supply (a deficiency); replenish."

Note that in quotations below, the romanization of Chinese is standardized into Pinyin, for instance, Wade-Giles ch'i, Simplified Wade chhi (used by Needham), and other transcription systems are converted to qi (氣, "breath; vital force").

The archeological discovery and analysis of medical manuscripts in the 1970s revealed that the origins of Chinese sexual cultivation techniques dated back to at least the Warring States period (c. 475–221 BCE), rather than the early Han dynasty (202 BCE-220 CE), as previously believed (Needham and Lu 1983: 199).

Although none of them directly refer to the huanjing bunao 還精補腦, "returning the semen/essence to replenish the brain") techniques, three sexual cultivation bamboo-slip manuscripts mention aspects later associated with essence retention, accumulating and enclosing jing within the body, stimulating the penis, contracting the anus, and controlled stages of intercourse with ejaculation, all of which were believed to increase longevity and spiritual enlightenment.

(Harper 1998: 443, 456-458) Both the Shiwen and the Tianxia zhidao tan below describe accumulating and enclosing qing ("semen; life essence") in an enigmatic corporal space called the yubi (玉閉, "jade closure"), where shenming (神明, "spiritual illumination") occurs.

Second, the He yinyang (合陰陽, Conjoining/Uniting Yin and Yang; a standard term for sexual intercourse) manuscript begins with a jargonized method for doing it, Grip the hands [make a fist with the thumb tucked in], and emerge at the Yang side [outside] of the wrists; Stroke the elbow chambers; Press [or go to] the side of the underarms; Ascend the stove trivet [between the breasts]; Press the neck zone; Stroke the receiving canister [pelvic region]; Cover the encircling ring [waist]; Descend the broken basin [clavicle]; Cross the sweet-liquor ford [breasts]; Skim the Spurting Sea [navel]; Ascend Constancy Mountain [female genitals]; Enter the dark gate [vagina]; Ride the coital muscle [responsible for the female orgasm]; Suck the essence and spirit upward.

1294–1307), compiler of the Lishi zhenxian tidao tongjian (歷世真仙體道通鋻, Comprehensive Mirror of Immortals Who Embodied the Way Through the Ages), notes he chose to omit the tradition that "Some say that Sire Rong Cheng obtained the art of 'riding the woman,' by which one firmly grasps [the seminal vesicle] in order not to leak out the semen [but rather] cause it to return and so nourish the brain" because it probably resulted as "an erroneous divergence [from the earlier legend] by later generations."

Today, men do calisthenics and breathing exercises, revert their sperm to repair the brain, follow dietary rules, regulate their activity and rest, take medicines, give thought to their inner gods to maintain their own integrity, undergo prohibitions, wear amulets and seals from their belts, and keep at a distance all who might harm their lives.

(5, Ware 1966: 103) The "Resolving Hesitations" chapter praises the secret huanjing bunao practice, which had always been orally transmitted.On the technology of sex at least ten authors have written, some explaining how it can replenish and restore injuries and losses, others telling how to cure many diseases by its aid, others again describing the gathering of the Yin force to benefit the Yang, others showing how it can increase one's years and protract one's longevity.

Besides, the union of Yin and Yang in sexual life should not be wholly given up, for if a man does not have intercourse he will contract the diseases of obstruction and blockage by his slothful sitting, and end by those which arise from celibate depression and pent-up resentment—what good will that do for his longevity?

The 2nd or 3rd century Huangting waijing yujing (黃庭外景玉經, Jade Manual of the External Radiance of the Yellow Courts; compare the Shangqing revelations Inner Scripture) is "filled with cryptic expressions and divine names" designed to exclude uninformed readers, and is addressed to learned Daoists already familiar with huanjing bunao techniques (Maspero 1981: 488, 523).

The ensuing passage quotes an anonymous Xianjing (仙經, Scripture on Transcendence/Immortality") that gives details of how to practice huanjing bunao, where the diverted "jing" seems to be ordinary semen and not supernatrural "jingqi" (精氣, "sexual energy; vitality") (Wile 1992: 48).

The fact that it passed into the bladder and was later urinated always escaped the notice of the Daoists, and "over more than two thousand years a great structure of theory grew up" concerning how the precious secretion of jing essence was conveyed up into the head and ultimately to the center of the body for the preparation of the internal elixir (1983: 197–198).

(Wile 1992: 101) The pre-Sui c. 4th century Yufang mijue (玉房秘訣, Secrets of the Jade Chamber) expands the semantic range of the huanjing bunao ("return the sperm/essence to nourish the brain") vocabulary.

The c. 5th century Qingling zhenren Peijun zhuan (清靈真人裴君傳, Biography of Lord Pei, the Realized Person of Pure Refinement) (The couple) should be free from the effects of wine or repletion of food, and they should be clean of body, for otherwise illness and disease will afflict them.

The woman guards (controls) her heart (i.e., her emotions) and 'nourishes her shen,' not allowing the refined fire to move (煉火不動, lian huo butong, i.e., refraining from orgasm), but making the qi of her two breasts descend into her reins, and then also rise up from there (along the spinal column) to reach the brain.

In Sui (561-618) and Tang (618-907) dynasty sex manuals, the "return," "circulation," or "rising" of the jing takes place "naturally as a result of simultaneous stimulation and reservatus; and that male and female sexual energy usually are treated in separate passages in the texts and never explicitly linked" (Wile 1992: 48).

The Tang Fangzhong buyi (房中補益, Health Benefits of the Bedchamber) was preserved in Sun Simiao's 652 classic medical reference Qianjin yaofang (Essential Prescriptions Worth a Thousand) (chapter 83).

Second, it presents meditative visualizations and yogic postures for precoital preparation and postcoital absorption, for instance, "Imagine a red color within the navel the size of a hen's egg" for deep penetration without arousing the jing.

The text then goes on to explain the chenghu (垂壺, "riding the wine-pot") technique of "applying the perineal pressure in coitus thesauratus with the heel rather than the hand", and quotes an old Daoist saying that: "Who wishes life unending to attain, Must raise the essence to restore the brain [運精補腦]."

During the Tang dynasty, Neidan (Inner Alchemy) became popular and huijing benao took on a different meaning that refers to the repeated cycling of the essence in the first stage of the practice, called zhoutian (周天, "celestial circuit; continuously circular movement of the universe") (Despeux 2008: 515).

The c. 1020 Yunü sunyi (御女損益, Dangers and Benefits of Intercourse with Women) is chapter 6 of the Yangxing yanming lu (養性延命錄, "On Nourishing Inner Nature and Extending Life"), attributed to Tao Hongjing or Sun Simiao.

It presents some new themes, such as postejaculatory remediation, advising to supplement leaked semen by engaging in daoyin exercise to "circulate energy internally", and an early description of cloudy urine from retrograde ejaculation (Pfister 2022: 345).

Although the Daoist practice of "returning the seminal essence to replenish the brain" may seem to be a uniquely Orientalist mystery, there are historical counterparts in the fields of Ancient Greek medicine and Tantric sex.

But the act must not be performed down to its natural consequences; it should be controlled by pranayama [Yogic breath-control], in such a manner that the semen goes its way backwards, not flowing downwards but ascending upwards, until it reaches the top of the head, hence to vanish into the uncreated source of the Whole" (Tucci 1949: 242).

Although Vajrayana incorporated older Buddhist and Hindu thought, the "conception of the coitus reservatus supplying a shortcut to complete enlightenment was an entirely new element, in that form unknown in pre-Vajrayana Buddhism" (van Gulik 1971: 343).

Finally, Joseph Needham says a sexual ritual of the Hindu Vaishnava Sahajiya tradition has an equivalence to Chinese huanjing bunao ("making the jing, or seminal essence, return") that is "too close to be accidental" (1956: 428).