A man and woman may engage in sexual intercourse with the objective of conception.
Some people engage in hate sex, which occurs between two people who strongly dislike or annoy each other.
It releases tension, elevates mood, and may create a profound sense of relaxation, especially in the postcoital period.
From a biochemical perspective, sex causes the release of endorphins and increases levels of white blood cells that actually boost the immune system.
Sexual arousal can also be experienced from foreplay and flirting, and from fetish or BDSM activities, or other erotic activities.
Most commonly, people engage in sexual activity because of the sexual desire generated by a person to whom they feel sexual attraction; but they may engage in sexual activity for the physical satisfaction they achieve in the absence of attraction for another, as in the case of casual or social sex.
3 (June 2007): 357–68) reported that sexual behavior with a partner on one day significantly predicted lower negative mood and stress, and higher positive mood, on the following day.
Fetishism can take many forms ranging from the desire for certain body parts, for example large breasts, armpits or foot worship.
Two examples that are criminal offences in most jurisdictions are sexual assault and sexual activity with a person below the local age of consent.
Sexual activity can be classified in a number of ways: acts which involve one person (also called autoeroticism) such as masturbation, or two or more people such as vaginal sex, anal sex, oral sex or mutual masturbation.
In different cultures and countries, various sexual activities may be lawful or illegal in regards to the age, gender, marital status or other factors of the participants, or otherwise contrary to social norms or generally accepted sexual morals.
Sexual dysfunction is the inability to react emotionally or physically to sexual stimulation in a way projected of the average healthy person; it can affect different stages in the sexual response cycles, which are desire, excitement and orgasm.