Frot is a slang term derived from frottage (ult. from the French verb frotter, "to rub") describing a form of non-penetrative male/male sex that usually but not always involves direct penis-to-penis contact.

The term "frot" was originally popularized by gay male activists who disparaged the practice of anal sex. The term has since evolved to encompass a variety of preferences for the act, which may or may not imply particular attitudes towards other sexual activities.

Owing to its non-penetrative character, frot has the safe sex advantage of minimizing the transmission risk for HIV/AIDS, and may also help to lower the risk of certain other sexually transmitted infections, without the inconvenience of purchasing condoms and condom-safe lubricants.

Genito-genital sex or genital-genital (GG) sex is a physically descriptive term for sex in which there is contact between the genitals, in the same naming convention as "genital-anal sex" and "genital-oral sex". This type of sexual intimacy is not restricted to humans. "GG rubbing" is a term frequently used by primatologists to describe the act among female bonobos, and is sometimes used in reference to "GG rubbing" among bonobo males, under the term "penis fencing." Thus, penis-to-penis rubbing between males is thought, according to varying evolutionary theorists, to have existed before the development of hominids into humans and bonobos, and may or may not have occurred in the homosexual activity of both of these genetically related species.