Sexual arousal

"Turn on" redirects here. For the very shortlived late 1960s TV series, see Turn-On.

Sexual arousal is the process and state of an animal being ready for sexual activity.

Human sexual arousal

Unlike most other animals, human beings of both sexes are potentially capable of sexual arousal throughout the year, therefore, there is no human mating season. Things that precipitate human sexual arousal are colloquially known as turn-ons. Turn-ons may be physical, mental, or sexual fetish in nature. Given the right stimulation, sexual arousal in humans will typically end in an orgasm, but may be pursued for its own sake, even in the absence of an orgasm.

Causes of human sexual arousal

See also: Sexual attraction

Includes, but is not limited to:

The physical attractiveness, eye contact, smell, warmth, and touch of a (potential) sexual partner
Feeling sexy, desired
Sexual foreplay
Erotic thoughts, fantasies or dreams
Presence of fetished objects
Pornography
Erotica
Sex in advertising
Masturbation
Sexual roleplaying
Voyeurism
Exhibitionism, particularly being flashed an otherwise taboo part of the body, such as the breasts, buttocks or genitalia — arousal in this case most often happens when a woman flashes a person or group of people of the opposite (or, in the case of lesbian viewers, sometimes the same) sex. Evidence of the popular extent of this arousal is evident in the popularity in Western society of the Girls Gone Wild enterprise and similar products.
No reason at all

Signs of possible human sexual arousal

Female sexual arousal:
- Increase in breast size
- Vaginal lubrication
- Vasocongestion of the vaginal walls
- Clitoral tumescence and erection
- More visible venous patterns across the breasts
- Elevation of the uterus and stretching of the vagina
- Change in shape, color and size of the labia majora and labia minora
Male sexual arousal:
- Penile tumescence and erection (usually the most prominent and reliable sign of sexual arousal in males; however, adolescent males experience frequent 'non-sexual' erections stemming from their high level of testosterone.)
- Retraction and tightening of the foreskin if present, often exposing the glans penis if not normally exposed (though this is not always the case)
- Emission of pre-ejaculatory fluid
- Swelling of the testes
- Ascension of the testes
- Tensing and thickening of the scrotum
In either sex:
- Increase in breathing rate
- Increase in blood pressure
- Increase in muscle tone (myotonia)
- Increase in heart rate (tachycardia)
- Vasocongestion of the skin ("sex flush")
- Slight or extreme dilation of the pupils (though especially so with females)
- Erection of the nipples (especially upon direct stimulation)

Human sexual response cycle

During the 1950s and 1960s, William H. Masters and Virginia E. Johnson conducted many important studies within the field of human sexuality. In 1966, the two released a book, Human Sexual Response, detailing four stages of physiological changes in humans during sexual stimulation. These phases, in order of their occurrence, are excitement, plateau, orgasmic, and resolution.

See human sexual response cycle.

Genital procedures and sexual arousal

Scientific data shows that male circumcision may cause neurological changes in the human brain, which is suggested to lower sexual excitability (Mackey, 1997), due to decreased sensitivity (as a result of keratinization of the surface of the glans penis). This is contested Another study suggested that arousal of a circumcised male's female partner is also impacted. [http://www.nzma.org.nz/journal/116-1181/595/.

Sexual arousal in other animals

It is not completely understood how other animals relate sexually, but current research studies suggest that animals, like humans, enjoy sexual relations. This is especially noted in dogs, dolphins, and bonobos.