There is no clear borderline between sexual and nonsexual enjoyment of touching someone else's body. For example, holding hands may or may not have a sexual connotation, depending on culture, situation and other factors. The distinction between sexual and nonsexual behavior can be relevant due to social rules.
Some criteria that may be applied are:
- the body parts involved (see also intimate parts)
- physical signs of sexual arousal
- subjective feeling
Some forms of sex involve someone else, but not touching the other:
Consenting noncommercial sexual behavior between people usually implies some kind of emotional bond, at least during the sex. Opinions and norms vary about whether a certain intensity and durability of this bond should be a prerequisite for sex (see also below).
Like other primates, Homo sapiens use sexuality for reproduction and for maintenance of social bonds. It is generally acknowledged that children are capable of feeling sexual pleasure, even if they are not yet able to engage in sexual intercourse with each other, and/or are not yet biologically able to reproduce. Yet, child sexuality has historically been severely limited in western societies; in the late 19th century, the hysteria surrounding so-called "self-abuse" (masturbation) among children reached its peak and fueled the adoption of circumcision in some cultures.
As with other behaviors, our high intelligence and complex societies have produced in us the most complicated sexual behaviors of any animal.
Most people enjoy some sexual activities. However, most societies have defined some sexual activities as inappropriate (wrong person, wrong activity, wrong time, etc.) Many sexual activities can be engaged in by same sex or opposite sex partners. However some, (most notably sexual intercourse), can only be engaged in by partners of opposite sexes.
Most people experiment with a range of sexual activities during their lives, though they tend to engage in only a few of these regularly. Some people enjoy many different sexual activities, while others avoid sexual activities altogether for religious or other reasons (see chastity, sexual abstinence). There is also a widespread belief that sex acts are devalued when engaged in outside of a long-term, monogamous romantic relationship.
Sexual behavior, like other kinds of social activity, is generally governed by rules of etiquette which are culturally specific and vary widely (see sexual morality, sexual norms).
Some people engage in various sexual activities as a business transaction; this is called prostitution.
Nearly all cultures consider it a serious crime to force someone to engage in sexual behavior or to engage in sexual behavior with someone who does not consent. This is called sexual assault, and in the case of sexual intercourse it is called rape, the most serious kind of sexual assault. Details on this distinction may vary. Also, precisely what constitutes effective consent to have sex varies from culture to culture and is frequently debated. Laws regulating what constitutes consent, including the minimum age at which a person can consent to have sex, are frequently the subject of debate; see age of consent.
The wide range of human sexual activities includes:
- vaginal intercourse
- oral sex (cunnilingus, fellatio, rimming, felching, snowballing)
- anal sex
- sexual roleplaying
- sexual fetishism
All sexual behaviors that involve contact with another person or the body fluids of another person entail some risk of transmission of sexually transmitted diseases, which is why safer sex techniques are recommended.
Many people enjoy fantasizing about, or reading or viewing depictions of, sexual fantasies of activities that they do not wish to engage in in their own lives, or that they would be unable to engage in in their own lives (see pornography and erotica).
See also: sex, human sexuality, child sexuality, sexual orientation, gender and sexuality studies, obstetrics and gynecology, sexual arousal, pornography, X-rated, Sexual ritual, Love-shyness, Sex positivity, Sex education.