Human sexual activity, human sexual practice or human sexual behaviour is the manner in which humans experience and express their sexuality. People engage in a variety of sexual acts, ranging from activities done alone (e.g., masturbation) to acts with another person (e.g., sexual intercourse, non-penetrative sex, oral sex, etc.) in varying patterns of frequency, for a wide variety of reasons. Sexual activity usually results in sexual arousal and physiological changes in the aroused person, some of which are pronounced while others are more subtle. Sexual activity may also include conduct and activities which are intended to arouse the sexual interest of another or enhance the sex life of another, such as strategies to find or attract partners (courtship and display behaviour), or personal interactions between individuals (for instance, foreplay or BDSM). Sexual activity may follow sexual arousal.
Human sexual activity has sociological, cognitive, emotional, behavioural and biological aspects; these include personal bonding, sharing emotions and the physiology of the reproductive system, sex drive, sexual intercourse and sexual behaviour in all its forms.
In some cultures, sexual activity is considered acceptable only within marriage, while premarital and extramarital sex are taboo. Some sexual activities are illegal either universally or in some countries or subnational jurisdictions, while some are considered contrary to the norms of certain societies or cultures. Two examples that are criminal offences in most jurisdictions are sexual assault and sexual activity with a person below the local age of consent.