Orgasm in the context of Phallus

Masturbation is a form of autoeroticism in which a person sexually stimulates their own genitals for sexual arousal or other sexual pleasure, usually to the point of orgasm. Stimulation may involve the use of hands, everyday objects, sex toys, or more rarely, the mouth (autofellatio and autocunnilingus). Masturbation may also be performed with a sex partner, either masturbating together or watching the other partner masturbate, known as "mutual masturbation".

Masturbation is frequent in both sexes. Various medical and psychological benefits have been attributed to a healthy attitude toward sexual activity in general and to masturbation in particular. No causal relationship between masturbation and any form of mental or physical disorder has been found. Masturbation is considered by clinicians to be a healthy, normal part of sexual enjoyment. It is found to be harmful only as a result of certain medical conditions such as Peyronie's disease and hard flaccid syndrome.

Anal sex or anal intercourse principally means the insertion and thrusting of the erect penis into a person's anus, or anus and rectum, for sexual pleasure. Other forms of anal sex include anal fingering, the use of sex toys, anilingus, and pegging. Although anal sex most commonly means penile–anal penetration, sources sometimes use anal intercourse to exclusively denote penile–anal penetration, and anal sex to denote any form of anal sexual activity, especially between pairings as opposed to anal masturbation.

While anal sex is commonly associated with male homosexuality, research shows that not all homosexual men engage in anal sex and that it is not uncommon in heterosexual relationships. Types of anal sex can also be part of lesbian sexual practices. People may experience pleasure from anal sex by stimulation of the anal nerve endings, and orgasm may be achieved through anal penetration – by indirect stimulation of the prostate in men, indirect stimulation of the clitoris or an area in the vagina (sometimes called the G-spot) in women, and other sensory nerves (especially the pudendal nerve). People may also find anal sex painful, sometimes extremely so, which may be due to psychological factors in some cases.

Sexual arousal (also known as sexual excitement) describes the physiological and psychological responses in preparation for sexual intercourse or when exposed to sexual stimuli. A number of physiological responses occur in the body and mind as preparation for sexual intercourse, and continue during intercourse. Male arousal will lead to an erection, and in female arousal, the body's response is engorged sexual tissues such as nipples, clitoris, vaginal walls, and vaginal lubrication.

Mental stimuli and physical stimuli such as touch, and the internal fluctuation of hormones, can influence sexual arousal. Sexual arousal has several stages and may not lead to any actual sexual activity beyond a mental arousal and the physiological changes that accompany it. Given sufficient sexual stimulation, sexual arousal reaches its climax during an orgasm. It may also be pursued for its own sake, even in the absence of an orgasm.

Autoeroticism (also known as autoerotism or self-gratification) is sexual activity involving only one participant. It is the use of one's own body and mind to stimulate oneself sexually.

As an extension of masturbation, it usually means one of several activities done by oneself to fulfill their own sexual desire. Masturbation has a similar meaning, but is not synonymous; masturbation is only physical stimulation of the genitals by oneself while autoeroticism encompasses all stimulation by oneself (masturbation or sexual thoughts), as well as involuntary experiences (wet dreams or spontaneous sexual arousal).

Sexual stimulation is anything that leads to sexual arousal or orgasm. This thing can be physical or of other senses, and is known as a stimulus.

Sexual stimulation is a broad term, usually understood to mean physical touching of the genitals or other body parts. The term can, however, include stimuli affecting the mind (sexual fantasy), or senses other than touch (such as sight, smell, or hearing). Sufficient physical stimulation of the genitals usually results in an orgasm. Stimulation can be by oneself (masturbation or sexual fantasy) or by a sexual partner (sexual intercourse or other sexual activity), by use of objects or tools, or by some combination of these methods.

Endorphins (contracted from endogenous morphine) are peptides produced in the brain that block the perception of pain and increase feelings of wellbeing. They are produced and stored in the pituitary gland of the brain. Endorphins are endogenous painkillers often produced in the brain and adrenal medulla during physical exercise or orgasm and inhibit pain, muscle cramps, and relieve stress.

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 vibrator, sometimes described as a massager, is a sex toy that is used on the body to produce pleasurable sexual stimulation. There are many different shapes and models of vibrators. Most modern vibrators contain an electric-powered device that pulsates or throbs. Vibrators can be used for both solo play and partnered play by one or more people. Devices exist to be used by couples to stimulate the genitals of both partners. They can be applied to erogenous zones – such as the vulva, vagina, penis, scrotum, anus, or rectum – for sexual stimulation, for the release of sexual frustration, and to achieve orgasm. Vibrators may be recommended by sex therapists for women who have difficulty reaching orgasm through masturbation or intercourse.

Ejaculation is the discharge of semen (the ejaculate; normally containing sperm) from the penis through the urethra. It is the final stage and natural objective of male sexual stimulation, and an essential component of natural conception. After forming an erection, many men emit pre-ejaculatory fluid during stimulation prior to ejaculating. Ejaculation involves involuntary contractions of the pelvic floor and is normally linked with orgasm. It is a normal part of male human sexual development.

Ejaculation can occur spontaneously during sleep (a nocturnal emission or "wet dream") or in rare cases because of prostatic disease. Anejaculation is the condition of being unable to ejaculate. Dysejaculation is an ejaculation that is painful or uncomfortable. Retrograde ejaculation is the backward flow of semen from the urethra into the bladder. Premature ejaculation happens shortly after initiating sexual activity, and hinders prolonged sexual intercourse. A vasectomy alters the composition of the ejaculate as a form of birth control.

Cunnilingus is an oral sex act consisting of the stimulation of a vulva by using the tongue and lips. The clitoris is the most sexually sensitive part of the vulva, and its stimulation may result in a woman becoming sexually aroused or achieving orgasm.

Cunnilingus can be sexually arousing for participants and may be performed by a sexual partner as foreplay to incite sexual arousal before other sexual activities (such as vaginal or anal intercourse) or as an erotic and physically intimate act on its own. Cunnilingus can be a risk for contracting sexually transmitted infections (STIs), but the transmission risk from oral sex, especially of HIV, is significantly lower than for vaginal or anal sex.

In amniotes, the clitoris (/ˈklɪtərɪs/ KLIT-ər-iss or /klɪˈtɔːrɪs/ klih-TOR-iss; pl.: clitorises or clitorides) is a female sex organ. In humans, it is the vulva's most erogenous area and generally the primary anatomical source of female sexual pleasure. The clitoris is a complex structure, and its size and sensitivity can vary. The visible portion, the glans, of the clitoris is typically roughly the size and shape of a pea and is estimated to have more than 10,000 nerve endings.

Sexological, medical, and psychological debate has focused on the clitoris, and it has been subject to social constructionist analyses and studies. Such discussions range from anatomical accuracy, gender inequality, female genital mutilation, and orgasmic factors and their physiological explanation for the G-spot. The only known purpose of the human clitoris is to provide sexual pleasure.

The G-spot, also called the Gräfenberg spot (for German gynecologist Ernst Gräfenberg), is characterized as an erogenous area of the vagina that, when stimulated, may lead to strong sexual arousal, powerful orgasms and potential female ejaculation. It is typically reported to be located 5–8 cm (2–3 in) up the front (anterior) vaginal wall between the vaginal opening and the urethra and is a sensitive area that may be part of the female prostate.

The existence of the G-spot has not been proven, nor has the source of female ejaculation. Although the G-spot has been studied since the 1940s, disagreement persists over its existence as a distinct structure, definition and location. The G-spot may be an extension of the clitoris, which together may be the cause of orgasms experienced vaginally. Sexologists and other researchers are concerned that women may consider themselves to be dysfunctional if they do not experience G-spot stimulation, and emphasize that not experiencing it is normal.

An erogenous zone (from Greek ἔρως, érōs "love"; and English -genous "producing", from Greek -γενής, -genḗs "born") is an area of the human body that has heightened sensitivity, the stimulation of which may generate a sexual response such as relaxation, sexual fantasies, sexual arousal, and orgasm.

Erogenous zones are located all over the human body, but the sensitivity of each varies, and depends on concentrations of nerve endings that can provide pleasurable sensations when stimulated. The touching of another person's erogenous zone is regarded as an act of physical intimacy. Whether a person finds stimulation in these areas to be pleasurable or objectionable depends on a range of factors, including their level of arousal, the circumstances in which it takes place, the cultural context, the nature of the relationship between the partners, and the partners' personal histories.

The human sexual response cycle is a four-stage model of physiological responses to sexual stimulation, which, in order of their occurrence, are the excitement, plateau, orgasmic, and resolution phases. This physiological response model was first formulated by William H. Masters and Virginia E. Johnson, in their 1966 book Human Sexual Response. Since that time, other models regarding human sexual response have been formulated by several scholars who have criticized certain inaccuracies in the human sexual response cycle model.

Sexual dysfunction is difficulty experienced by an individual or partners during any stage of normal sexual activity, including physical pleasure, desire, preference, arousal, or orgasm. The World Health Organization defines sexual dysfunction as a "person's inability to participate in a sexual relationship as they would wish". This definition is broad and is subject to many interpretations. A diagnosis of sexual dysfunction under the DSM-5 requires a person to feel extreme distress and interpersonal strain for a minimum of six months (except for substance- or medication-induced sexual dysfunction). Sexual dysfunction can have a profound impact on an individual's perceived quality of sexual life. The term sexual disorder may not only refer to physical sexual dysfunction, but to paraphilias as well; this is sometimes termed disorder of sexual preference.

A thorough sexual history and assessment of general health and other sexual problems (if any) are important when assessing sexual dysfunction, because it is usually correlated with other psychiatric issues, such as mood disorders, eating and anxiety disorders, and schizophrenia. Assessing performance anxiety, guilt, stress, and worry are integral to the optimal management of sexual dysfunction. Many of the sexual dysfunctions that are defined are based on the human sexual response cycle proposed by William H. Masters and Virginia E. Johnson, and modified by Helen Singer Kaplan.

Anorgasmia is a type of sexual dysfunction in which a person cannot achieve orgasm despite adequate sexual stimulation. Anorgasmia is far more common in females (4.6%) than in males and is especially rare in younger men. The problem is greater in women who are post-menopausal. In males, it is most closely associated with delayed ejaculation. Anorgasmia can often cause sexual frustration.