PinV sex is an abbreviation of the term "penis in vagina sex." This is sexual intercourse that involves a penis entering a vagina. This is sometimes referred to as vaginal intercourse. However, a vagina being penetrated by a dildo or a hand would also fall into this category. PinV refers exclusively to the penetration of a vagina with a penis.
The term PinV sex was coined as part of the movement away from recognizing one thing (traditionally penis in vagina intercourse) as "sex". It is now acknowledged that there are many ways to express sexuality (anal sex, oral sex, manual sex, mutual masturbation, strap-on sex, and so on) and that they are all valid and real forms of sex. The term PinV sex serves to categorize penis in vagina intercourse as simply one of many forms of sexual expression.
