Masturbation refers to sexual stimulation, especially of one's own genitals (self masturbation) and often to the point of orgasm[1], which is performed manually, by other types of bodily contact (except for sexual intercourse), by use of objects or tools, or by some combination of these methods.[2] Masturbation is the most common form of autoeroticism[citation needed], and the two words are often used as synonyms, although masturbation with a partner (mutual masturbation) is also common. Animal masturbation has been observed in many species, both in the wild and in captivity.

Ways of masturbating common to members of both sexes include pressing or rubbing the genital area, either with the fingers or against an object such as a pillow; inserting fingers or an object into the anus (see anal masturbation); and stimulating the penis or vulva with electric vibrators, which may also be inserted into the vagina or anus. Members of both sexes may also enjoy touching, rubbing, or pinching the nipples or other erogenous zones while masturbating. Both sexes sometimes apply lubricating substances to intensify sensation.
Reading or viewing pornography, or sexual fantasy, are often common adjuncts to masturbation. Often people will call upon memories during masturbation. Masturbation activities are often ritualised. Various fetishes and paraphilias can also play a part in the masturbation ritual. Some potentially harmful or fatal activities include autoerotic asphyxiation and self-bondage.
Some people get sexual pleasure by inserting objects into the urethra (the tube through which urine and, in men, semen, flows).[7] If these objects are urethral sounds, the practice is known as "sounding".[8] Other objects such as ball point pens and thermometers are sometimes used, although this practice can lead to injury and/or infection.[9] Some people masturbate by using machines that simulate intercourse.
Men and women may masturbate until they are close to orgasm, stop for a while to reduce excitement, and then resume masturbating. They may repeat this cycle multiple times. Called "edging", this "stop and go" build up can achieve even stronger orgasms. Rarely, people quit stimulation just before orgasm to retain the heightened energy that normally comes down after orgasm[10]. Doing this could lead to temporary discomfort due to pelvic congestion.
Austrian psychoanalyst Wilhelm Reich in his 1922 essay Concerning Specific Forms of Masturbation tried to identify healthy and unhealthy forms of masturbation. He tried to relate the way people masturbated to their degree of inclination towards the opposite sex and to their psycho-sexual pathologies.