You know what it feels like, but do you actually know what is happening when your body ejaculates? Well, don’t feel bad, scientists don’t know a whole lot about it either. It turns out, there actually hasn’t been much research into what physical mechanisms are involved when a man orgasms. The medical volume Standard Practice in Sexual Medicine, 2006, states that “a non-disputed physio-anatomic description of the mechanism of human ejaculation still has yet to be produced.” That basically means we don’t know exactly what happens. But we do know some things.
You don’t even need to be touched to ejaculate. It has been found that some men with spinal cord injuries and no feeling in their genitals can still ejaculate.
You don’t need to think to ejaculate. Researchers have discovered that merely applying electrical stimulation to a certain area of the spinal cord of rats caused them to ejaculate, leading some to theorize it has more in common with a reflex.
But there is in fact, a mental component to ejaculation. They still have not discovered an orgasm center in the brain. Brain imaging done during patients experiencing orgasms has been unable to isolate one area of the brain that becomes particularly active during or right before orgasm. But men also are able to resist ejaculation.
You can orgasm and not ejaculate. This is not necessarily advisable, but there is a Tantric sex practice where the male holds in his ejaculate, which causes the fluid to be forced into the bladder where it is later expelled during urination. They claim it allows them to maintain their erection between orgasms. There has not been enough research into the potential physical dangers of this practice.
The medical profession still is divided on what exactly causes a man to ejaculate in the way that he does. For a while, it was a common belief that ejaculation was the release of pressure from the amount of semen built up in a chamber in the genitals. This has been disproven however as there has been no “chamber” discovered where the semen would build up. It was also found that there is no pressure buildup in the urethra either which would create that “feeling of inevitability.”
The male orgasm seems to be a multi-faceted, complex combination of mental and physical stimulation that culminates in the cavernovesicular reflex that expels semen from the urethra.