Definition: PIV sex is shorthand for "penis in vagina" sex - in other words, vaginal intercourse. Many people define sex as PIV. However this definition is problematic as sex for most individuals is also composed of many other activities - including oral sex, anal sex, and mutual masturbation. This is true even for heterosexuals who engage in PIV as a regular part of their sex lives.
When sex educators discuss PIV, they are usually referring to vaginal intercourse involving a cis-gendered man and cis-gendered woman. Some people will also describe strap-on sex as PIV, although that usage is rare.
Also Known As: vaginal intercourse, heterosexual sex
Alternate Spellings: P-I-V
Examples: PIV sex is the only type of sex that, when practiced by heterosexuals, carries a significant risk of pregnancy. However almost all forms of sex, including PIV, can put participants at risk of STDs.