Oral Sex - Student Health Center Oral Sex What is it? Oral sex refers to oral (mouth and tongue) stimulation of the genitals or other areas of the body Fellatio refers to oral stimulation of the penis; cunnilingus refers to oral stimulation of the vulva (the external part of the vagina) Anilingus refers to oral stimulation of the anal opening also known as "rimming" or anal oral sex The penis is the most sensitive at the