In the United States, reef sex is considered a rarely practiced form of sexual intercourse with the exception being the island of Key West, Florida. The term reef sex refers to placement of a snorkel, commonly used for ocean snorkeling, into the anus of a sexual partner during the act of oral or vaginal intercourse. The recipient merely relaxes as the 'snorkeler' then blows into the snorkel producing the characteristic ARRUUUUUUUUUGA! aesthetic. This is the culmination and essential step, thus completing a bout of reef sex.
Many Key West snorkeling companies offer night-time adventures where participants enjoy a happy hour at sea before retiring to their private bungalows and an excellent opportunity for their first experience with reef sex.