*The Yufang Mijue* records: Cai Nu asked, "Intercourse brings pleasure through ejaculation. Now, if we close and do not ejaculate, what pleasure is there?" Peng Zu answered, "When essence is discharged, the body becomes weary and fatigued; the ears suffer from buzzing noise; the eyes are heavy with sleepiness; the throat and pharynx become dry; the joints become loose and weak. Although there is momentary satisfaction, ultimately there is no joy.
If one engages in movement without ejaculation, qi and strength remain abundant; the body feels agile; the ears and eyes become clear and sharp. Even while self-restraining and remaining quiet, affection and love deepen, and one constantly feels a sense of insufficiency (of energy to be cultivated). How can this not be joyful?
It also states: Huang Di said, 'I wish to hear about the effects of moving without emitting.' Su Nu said, 'One movement without emission strengthens qi and power; two movements without emission make the ears and eyes acute; three movements without emission cause various diseases to vanish; four movements without emission ensure the peace of the five spirits; five movements without emission fill and lengthen the blood vessels; six movements without emission make the waist and back strong; seven movements without emission increase the strength of the buttocks and thighs; eight movements without emission make the body radiant; nine movements without emission preserve lifespan; ten movements without emission connect one to divine intelligence.'

*The Yufang Zhiyao* records: One who can engage in intercourse dozens of times a day without losing essence will have all diseases cured, and lifespan will increase daily. Furthermore, frequently changing female partners increases the benefit even more; changing more than ten women in one night is particularly excellent.
It also states: *The Xianjing* (Classic of Immortals) says: "The method of returning essence to nourish the brain: when essence surges greatly during intercourse and is about to exit, immediately use the middle two fingers of the left hand to press backward on the area behind the scrotum and in front of the anus. During vigorous activity, press firmly. Exhale slowly and deeply, and clench the teeth dozens of times. Do not hold the breath. Even if one attempts to emit, the essence cannot exit but instead returns upward from the penis into the brain. This method was transmitted by the immortal Lu Xiang, sealed with blood oaths, and must not be passed on recklessly, or one will suffer disaster."
It also states: If one wishes to practice sexual yoga for benefit and essence surges greatly, quickly look up with eyes wide open, gaze left, right, up, and down, contract the lower region (perineum), hold the breath, and the essence will naturally stop. Do not pass this on recklessly. A person who emits essence twice a month and twenty-four times a year can live to 120 years old, with a healthy complexion and free from disease.

*Qianjin Fang* (Essential Prescriptions Worth a Thousand Gold) records: In the early Zhen Guan era, an elderly villager over seventy years old came to me and said, "For the past few dozen days, my yang function has become increasingly robust. I desire to engage in sexual activities with my wife day and night, and it succeeds. I do not know if having this condition in old age is beneficial or harmful." I replied to him, "This is highly inauspicious. Have you not heard of lamp oil? When lamp oil is about to run out, the flame first dims and then suddenly brightens; after the brightness, it extinguishes. Now that you are near the end of your life (mulberry and elm), you should long have been conserving essence. For spring passion to erupt fiercely now, is this not abnormal? I privately worry for you. You must be cautious!" Forty days later, he fell ill and died suddenly. This was the result of carelessness. Therefore, those who are good at preserving health, whenever they feel excessive yang vigor, must carefully restrain it and must not indulge their desires to exhaust their energy and harm themselves. If one can control oneself once and avoid emission, it is like adding a large amount of oil. If one cannot control oneself and indulges in emission, it is like the lamp oil being about to go out and removing more oil. One must guard against this deeply.