The life instinct or Eros was one of the two basic instincts described by Freud in Beyond the Pleasure Principle. Life instinct stands opposed to the death instinct. The life instinct subsumed uninhibited sexual instincts, instinctual impulses inhibited in respect of their aim and sublimated, and the instincts of self-preservation.
In man, life instinct was managed by the Ego which is supervised by the Superego (for simplicity, can be considered as social rules and traditions with coercion to comply). As such much of life instinct, in particular, of sexuality, is often suppressed, constituting the darker side of man's unconscious. Higher level of Taoist meditation in its attempt to form a "diamond body" that is purified of man's darker side inevitably has to deal with the life instinct.
The theory behind this higher level of Taoist meditative practice is to drain the energy of this darker side by way of transforming this yin (feminine) energy to yang (masculine) energy through meditation. In short de-potentiate it. The practice of psychoanalysis also makes use of the concept of energy drain in its healing process. The latter approach is however pathological in nature, in which disturbing (or unmanageable) energy will be drained, through exposing this disturbing (unmanageable) aspect of the darker side to the conscious mind. Healing occurred when the patient can experience disturbing element in a safe (clinical) setting and is able to integrate it into their personality. Taoist theory is non-pathological in nature and is pro-active in its approach. A "saint-like" (to use a Christian concept) personality by de-energize one's darker side.
One question: is the approach of the Taoist scientific? Unfortunately as with other approach using one's psyche experience as raw data, a definitive proof of the nature of physical science is not available. Therefore this aspect of Taoist meditative practice can be to be, theoretically speaking, as scientific as the practice of psychoanalysis.
Another question: Does higher level of Taoist meditation really talk about the issue you have discussed? To answer this question, I have to quote from a Q&A between Master Liu Huayang and another Zen monk as described in Hui Ming Jing:
Q: I practice (calm) meditation and lead a secluded life, and I don't have erotic thoughts, can I reach the stage of complete control of my instinct necessary for Dharma achievement?
A: The practice of (calm) meditation and leading a secluded life can help one to maintain a life of celibacy. But that alone can't totally eradicate one's hidden urge and therefore one can't achieve Dharma. One must also practice the meditation that can transform such hidden energy by wind and fire into positive energy.