Frot (slang for frottage; ult. from the French verb frotter, "to rub") is a non-penetrative form of male-male sexual activity that usually involves direct penis-to-penis contact. The term was popularized by gay male activists who disparaged the practice of anal sex, but 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; however, it still carries the risk of skin-to-skin sexually transmitted infections, such as HPV and pubic lice (crabs), both of which can be transmitted even when lesions are not visible.