This possibility, sometimes called the "Poleaxe Hypothesis" or the "Knockout Hypothesis",  is now considered unlikely. A 1994 Learning Channel documentary on sex had fiber optic cameras inside the vagina of a woman while she had sexual intercourse. During her orgasm, her pelvic muscles contracted and her cervix repeatedly dipped into a pool of semen in the vaginal fornix, which might ensure that sperm would proceed by the external orifice of the uterus, making conception more likely.Evolutionary psychologists Christopher Ryan and Cacilda Jethá, in their discussion of the female orgasm, address how long it takes for females to achieve orgasm compared to males, and females ability to have multiple orgasms, hypothesizing how especially well suited to multiple partners and insemination this is. They quote primate sexuality specialist Alan Dixson in saying that the monogamy-maintenance explanation for female orgasm "seems far-fetched" because "females of other primate species, and particularly those with multimale-multifemale [promiscuous] mating systems such as macaques and chimpanzees, exhibit orgasmic responses in the absence of such bonding or the formation of stable family units." On the other hand, Dixson states that "Gibbons, which are primarily monogamous, do not exhibit obvious signs of female orgasm. "The female promiscuity explanation of female sexuality was echoed at least 12 years earlier by other evolutionary biologists, and there is increasing scientific awareness of the female proceptive phase.
However, the sensations in both sexes are extremely pleasurable and are often felt throughout the body, causing a mental state that is often described as transcendental, and with vasocongestion and associated pleasure comparable to that of a full-contractionary orgasm. For example, modern findings support distinction between ejaculation and male orgasm. For this reason, there are views on both sides as to whether these can be accurately defined as orgasms. Achieving orgasm
Orgasms can be achieved during a variety of activities, including vaginal, anal or oral sex, non-penetrative sex or masturbation. They may also be achieved by the use of a sex toy, such as a sensual vibrator or an erotic electrostimulation. Achieving orgasm by stimulation of the nipples or other erogenous zones is rarer. Multiple orgasms are also possible, especially in women, but they are also uncommon. Multiple orgasms are orgasms that occur within a short period of one another.In addition to physical stimulation, orgasm can be achieved from psychological arousal alone, such as during dreaming (nocturnal emission for males or females) or by forced orgasm. Orgasm by psychological stimulation alone was first reported among people who had spinal cord injury.