It's the only thing that feels better than diving into a cool lake on a sweltering day, biting into a juicy cheeseburger when you're starving, or even getting your wallet back after losing it on vacation abroad. An orgasm is that good. Which is why it bites that it doesn't happen more often. According to several major surveys, only 25 percent of women always climax during sex with a partner.
Human sex from the inside out
sexual intercourse | Description & Facts | Britannica
Ejaculation is the emission of semen, a mixture of fluids and sperm, from the male reproductive tract. Generally the result of physical or mental sexual stimulation, ejaculation accompanies almost all orgasms, though some men achieve orgasm without ejaculation either through purposeful training or through physical abnormalities in the reproductive tract. During the period of arousal that precedes ejaculation, glands of the male reproductive system produce pre-ejaculatory fluid that prepares the urethra for the movement of sperm. This fluid, largely secreted by an organ situated close to the base of the penis and called the bulbourethral gland, coats the urethra so that sperm are not damaged by their high-speed trajectory during ejaculation. During seminal emission, the bladder neck closes off, preventing retrograde seminal movement. Most men have some control over the process of seminal emission, and can delay it a bit as desired.
Women describe what an orgasm actually feels like
Although it seems simple enough, the male orgasm is actually a complex process. The typical result is ejaculation of fluid that may contain sperm through strong muscle contractions. These fluids nourish and support the sperm so they can live after ejaculation for a limited time. This mixture of fluid and sperm, known as semen, is what is moved through the urethra and out the penis during orgasm.
Ejaculation may feel like a glorious mess, as uncontrollable as an avalanche or a runaway train. Ejaculation is the endpoint of a process that begins with a touch. Skin covering the shaft and glans of the penis is filled with nerve endings sensitive to pressure and vibration. More touching further increases sensitivity, in a positive feedback loop that can build to a show-stopping involuntary eruption. When enough stimulation trips arousal over into orgasm, it also triggers a storm of activity in the three ejaculatory centers deep in the brain.