Sexual penetration in the context of "Mutual masturbation"

Sexual intercourse (also coitus or copulation) is a sexual activity typically involving the insertion of the erect male penis inside the female vagina and followed by thrusting motions for sexual pleasure, reproduction, or both. This is also known as vaginal intercourse or vaginal sex. Sexual penetration is an instinctive form of sexual behaviour and psychology among humans. Other forms of penetrative sexual intercourse include anal sex (penetration of the anus by the penis), oral sex (penetration of the mouth by the penis or oral penetration of the female genitalia), fingering (sexual penetration by the fingers) and penetration by use of a dildo (especially a strap-on dildo), and vibrators. These activities involve physical intimacy between two or more people and are usually used among humans solely for physical or emotional pleasure. They can contribute to human bonding.

There are different views on what constitutes sexual intercourse or other sexual activity, which can impact views of sexual health. Although sexual intercourse, particularly the term coitus, generally denotes penile–vaginal penetration and the possibility of creating offspring, it also commonly denotes penetrative oral sex and penile–anal sex, especially the latter. It usually encompasses sexual penetration, while non-penetrative sex has been labeled outercourse, but non-penetrative sex may also be considered sexual intercourse. Sex, often a shorthand for sexual intercourse, can mean any form of sexual activity. Because people can be at risk of contracting sexually transmitted infections during these activities, safer sex practices are recommended by health professionals to reduce transmission risk.

Penile–vaginal intercourse, or vaginal intercourse, is the insertion of an erect penis into a vagina. It is the primary form of copulation in mammals and a form of penetrative sexual intercourse in human sexuality. Synonyms are: vaginal sex, coitus (Latin: coitus per vaginam), (in elegant colloquial language) intimacy, or (poetic) lovemaking; some of which are used for other forms of intercourse as well. Cohabitation is a related term describing a living arrangement.

Various sex positions can be used. Following insertion, additional stimulation is often achieved through rhythmic pelvic thrusting or a gyration of the hips, among other techniques. The biological imperative is to achieve male ejaculation so that sperm can enter the female reproductive tract and fertilize the egg, thus beginning the next stage in human reproduction, pregnancy.

Non-penetrative sex or outercourse is sexual activity that usually does not include sexual penetration, but some forms, particularly when termed outercourse, include penetrative aspects, that may result from forms of fingering or oral sex. It generally excludes the penetrative aspects of vaginal, anal, or oral sex, but includes various forms of sexual and non-sexual activity, such as frottage, manual sex, mutual masturbation, kissing, or hugging.

People engage in non-penetrative sex for a variety of reasons, including as a form of foreplay or as a primary or preferred sexual act. Heterosexual couples may engage in non-penetrative sex as an alternative to penile-vaginal penetration, to preserve virginity, or as a type of birth control. Same-sex couples may also engage in non-penetrative sex to preserve virginity, with gay males using it as an alternative to anal penetration.

Rape is a type of sexual assault involving sexual intercourse, or other forms of sexual penetration, carried out against a person without their consent. The act may be carried out by physical force, coercion, abuse of authority, or against a person who is incapable of giving valid consent, such as one who is unconscious, incapacitated, has an intellectual disability, or is below the legal age of consent (statutory rape). The wrongness of the rape is not merely or, on many occasions even primarily, the violence against the body of the victim but the violence against the very person of the victim. The term rape is sometimes casually used interchangeably with the term sexual assault.

The rate of reporting, prosecuting and convicting for rape varies between jurisdictions. Internationally, the incidence of rapes recorded by the police during 2008 ranged, per 100,000 people, from 0.2 in Azerbaijan to 92.9 in Botswana with 6.3 in Lithuania as the median. Worldwide, reported instances of sexual violence, including rape, are primarily committed by males against females. Rape by strangers is usually less common than rape by people the victim knows, and male-on-male prison rapes are common and may be the least reported forms of rape.

Orgasm (from Greek ὀργασμός, orgasmos; "excitement, swelling"), sexual climax, or simply climax, is the sudden release of accumulated sexual excitement during the sexual response cycle, characterized by intense sexual pleasure resulting in rhythmic, involuntary muscular contractions in the pelvic region. Orgasms are controlled by the involuntary or autonomic nervous system and are experienced by both males and females; the body's response includes muscular spasms (in multiple areas), a general euphoric sensation, and, frequently, body movements and vocalizations. The period after orgasm (known as the resolution phase) is typically a relaxing experience due to the release of the neurohormones oxytocin and prolactin, as well as endorphins (or "endogenous morphine").

Human orgasms usually result from physical sexual stimulation of the penis in males (typically accompanied by ejaculation) and of the clitoris (and vagina) in females. Sexual stimulation can be by masturbation or with a sexual partner (penetrative sex, non-penetrative sex, or other sexual activity). Physical stimulation is not a requisite, as it is possible to reach orgasm through psychological means. Getting to orgasm may be difficult without a suitable psychological state. During sleep, a sex dream can trigger an orgasm and the release of sexual fluids (nocturnal emission).

The missionary position (or man-on-top position) is a sex position in which, generally, a woman lies on her back and spreads her legs and a man lies on top of her while they face each other and engage in vaginal intercourse. The position may also be used for other sexual activity, such as anal sex. It is commonly associated with heterosexual sexual activity, but is also used by same-sex couples. It may involve sexual penetration or non-penetrative sex (for example, intercrural sex), and its penile-vaginal aspect is an example of ventro-ventral (front-to-front) reproductive activity. Variations of the position allow varying degrees of clitoral stimulation, depth of penetration, participation on the part of the woman, and the likelihood and speed of orgasm.

The missionary position is the most common sex position, but it is not universally regarded as the most favoured one. The missionary position is often preferred by couples who enjoy the romantic aspects of ample skin-to-skin contact and opportunities to look into each other's eyes and kiss and caress each other. The position is also believed to be a good position for reproduction. During sexual activity, the missionary position allows the man to control the rhythm and depth of pelvic thrusting; it is also possible for the woman to thrust against him by moving her hips or pushing her feet against the bed, or squeeze him closer with her arms or legs. The position is not suitable for late stages of pregnancy, and is less desired when the woman wants to have greater control over the rhythm and depth of penetration during intercourse.

A dildo is a sex toy, often explicitly phallic in appearance, intended for sexual penetration or other sexual activity during masturbation or with sex partners. Dildos are made from a number of materials. The shape and size are typically that of a human penis, but there is a wide variation to accommodate the needs of different users.