Oral sex consists of all the sexual activities that involve the use of the mouth and throat to stimulate genitalia or anus.It is sometimes performed to the exclusion of all other forms of sexual activity, and may include the ingestion or absorption of semen or vaginal fluids.
It may also be that conceptually conflating sexual activity with vaginal intercourse and sexual function hinders and limits information about sexual behavior that non-heterosexual people may be engaging in, or information about heterosexuals who may be engaging in non–vaginal sexual activity.
Studies regarding the definition of sexual intercourse sometimes conflict.
Similarly, some gay men consider frotting or oral sex as ways of maintaining their virginities, with penile-anal penetration defined as sexual intercourse and resulting in virginity loss, while other gay men may define frotting or oral sex as their main forms of sexual activity.
Learner and Steinberg attribute researchers' focus on penile–vaginal sex to "the larger culture's preoccupation with this form of sexual activity," and have expressed concern that the "widespread, unquestioned equation of penile–vaginal intercourse with sex reflects a failure to examine systematically 'whether the respondent's understanding of the question [about sexual activity] matches what the researcher had in mind'".
During coitus, the partners orient their hips to allow the penis to move back and forth in the vagina to cause friction, typically without fully removing the penis.
In this way, they stimulate themselves and each other, often continuing until orgasm in either or both partners is achieved.
A 1999 study by the Kinsey Institute examined the definition of sex based on a 1991 random sample of 599 college students from 29 U. states; it reported that while "virtually every college student they surveyed considered penile–vaginal intercourse to be sex," and 19–20% said that anal intercourse was not sex, 60% said oral-genital contact (fellatio, cunnilingus) did not constitute having sex.
Similarly, a 2003 study published in the Canadian Journal of Human Sexuality focusing on definitions of having sex and noting studies concerning university students from the United States, the United Kingdom, and Australia reported that "while the vast majority of respondents (more than 97%) in these three studies included penile–vaginal intercourse in their definition of sex, fewer (between 70% and 90%) respondents considered penile-anal intercourse to constitute having sex" and that "oral-genital behaviours were defined as sex by between 32% and 58% of respondents".
These copulatory reflexes are controlled by hormones and facilitated by sexual pheromones.
Unlike mammalian copulation, where copulation is a reflex controlled by hormones and influenced by pheromones, human sexual intercourse is mostly a voluntary and learned activity that is performed in order to obtain sexual rewards (i.e., pleasure or procreation).
Another study by the Kinsey Institute sampled 484 people, ranging in ages 18–96.