The Buddha taught celibacy. If you read the descriptions of the eightfold path in the Pali nikayas, you will see "right action" includes abstaining from sex. One disciple of the Buddha who broke the monastic rule against sex is told he would be better off if he stuck his penis in burning coals or in the mouth of a poisonous snake than in a woman.
The Buddha makes it clear that walking the path means letting go of sex eventually. But, its also pointed out in the pali nikayas that you can be a householder and gain stream entry. You can be married and gain stream entry. And, as far as I could tell in my best investigation of the topic, you can be sexually active and gain stream entry.
But that doesn’t mean that it’s helpful to the path to be sexually active. Just that you can practice in spite of the defilements of lust brought about by sexual activity.
I am in a committed monogamous relationship. My wife has desires that I attend to. It seemed to me that practicing semen-retentive sex was the closest thing that a sexually active lay practitioner could get to the full-blown celibacy the Buddha recommends.
I am no expert on Vajrayana but I understand that semen retention is also practiced by Tibetan Lamas. I have read that in Vajrayana the spilling of semen is equated to the “killing of a buddha.” The sexual energies are repurposed into spiritual energy through yoga. The fact that sexual energy is used this way in Vajrayana indicates to me that it clearly has a tremendous importance, even if this importance is not specifically explained in the pali nikayas.
But I can’t make it past about 3 months. Eventually the energy builds up and its too strong. It creates an aching discomfort and a bad mood. I could meditate on death and the unattractive components of the body until all sexual desire is evaporated by this wouldn't suit my wife well. The only other option is transmutation. I've not found a source on how to do this kind of meditation.
I don’t know how to transmute the sexual energy into spiritual energy. I have not found anyone who could point to a source about how to do this, or who was willing to speak openly about it. Generally you are told you have to join the club and do 400,000 prostrations before you can learn even the basic practices. I can understand the desire to be secretive about some things but I do not believe that turning sexual energy into spiritual energy or drawing it up into your heart chakra is "dangerous" outside of the context of the guru system. I don't think these practices should be kept secret because someone in my position will need them and has little alternative.
I understand that some Vajrayana practices predate Vajrayana – kundalini yoga for example and some other tantric yogas, so perhaps there are Indian yoga teachers who will teach how to transmute sexual energy without their requiring a lifetime commitment to them. Even if they are not Buddhist, this skill is necessary – after enough time of practicing semen retentive sex there’s a limit where all you feel is aggravation that becomes an even larger hindrance to sex.
I am interested if anyone else has tried to practice semen-retention (continence) in sex while married or in a serious relationship in order to enhance their practice by getting closer to celibacy, and if anyone has found any sources that teach how to transmute one’s own sexual energy to spiritual energy or how to draw the energy upwards into the body.

