Which "Chinese sex-yoga" tradition would that be? From Wiki: "Many Taoist practitioners link the loss of ejaculatory fluids to the loss of vital life force: where excessive fluid loss results in premature aging, disease, and general fatigue. While some Taoists contend that one should never ejaculate, others provide a specific formula to determine the maximum amount of regular ejaculations in order to maintain health. The general idea is to limit the loss of fluids as much as possible to the level of your desired practice. As these sexual practices were passed down over the centuries, some practitioners have given less importance to the limiting of ejaculation. Nevertheless, the "retention of the semen" is one of the foundational tenets of Taoist sexual practice."
"Treasuring the jing involved sending it up into the brain. In order to send the jing into the brain, the male had to refrain from ejaculation during sex. According to some Taoists, if this was done, the jing would travel up the spine and nourish the brain instead of leaving the body." There's also this passage. If you believed the following you'd be well advised to keep it as part of the secret oral traditions! "Some Ming Dynasty Taoists believed that one way for men to achieve longevity . . . is by having intercourse with young virgins. Taoist sexual books recommended sex with pre-menstruating virgins. Zhao Liangpi concludes that the ideal is a virgin just under 14 years of age and women older than 18 should be avoided."
