If males were motivated by, and taken to the point of, orgasm in the same way as females, those advantageous qualities would not be needed, since self-interest would be enough. Fertility
There are theories that the female orgasm might increase fertility. For example, it has been suggested that the 30% reduction in size of the vagina could help clench onto the penis (much like, or perhaps caused by, the pubococcygeus muscles), which would make it more stimulating for the male (thus ensuring faster or more voluminous ejaculation). The British biologists Baker and Bellis have suggested that the female orgasm may have a peristalsis or "upsuck" action (similar to the esophagus ability to swallow when upside down), resulting in the retaining of favorable sperm and making conception more likely. They posited a role of female orgasm in sperm competition. The observation that women tend to reach orgasm more easily when they are ovulating also has led to the suggestion that it is tied to increasing fertility. Evolutionary biologist Robin Baker argues in Sperm Wars that occurrence and timing of orgasms are all a part of the female bodys unconscious strategy to collect and retain sperm from more evolutionary fit men. This theory suggests that an orgasm during intercourse functions as a bypass button to a womans natural cervical filter against sperm and pathogens, and that an orgasm before functions to strengthen the filter. Desmond Morris proposed that orgasm might facilitate conception by exhausting the female and keeping her horizontal, thus preventing the sperm from leaking out.
Medical aspects
Physiological responses
Masters and Johnson were some of the first researchers to study the sexual response cycle in the early 1960s, based on the observation of 382 women and 312 men. They described a cycle that begins with excitement as blood rushes into the genitals, then reaches a plateau during which they are fully aroused, which leads to orgasm, and finally resolution, in which the blood leaves the genitals.In the 1970s, Helen Singer Kaplan added the category of desire to the cycle, which she argued precedes sexual excitation. She stated that emotions of anxiety, defensiveness and the failure of communication can interfere with desire and orgasm. In the late 1980s and after, Rosemary Basson proposed a more cyclical alternative to what had largely been viewed as linear progression. In her model, desire feeds arousal and orgasm, and is in turn fueled by the rest of the orgasmic cycle. Rather than orgasm being the peak of the sexual experience, she suggested that it is just one point in the circle and that people could feel sexually satisfied at any stage, reducing the focus on climax as an end-goal of all sexual activity. Males
As a man nears orgasm during stimulation of the penis, he feels an intense and highly pleasurable pulsating sensation of neuromuscular euphoria. These pulsating sensations originates from the contractions of pelvic floor muscles that begin in the anal sphincter and travels to the tip of the penis, commonly described as a "throbbing" or "tingling" sensation.