Oral sex refers to oral (mouth and/or tongue) stimulation of the genitals. Fellatio is the Latin term for oral stimulation of the male genitals. Cunnilingus is the Latin term for oral stimulation of the female genitals. Anilingus (sometimes called “rimming”) refers to oral-anal contact.
Historically, oral sex was perceived among heterosexual couples as not only more intimate than intercourse but also to be reserved for those who were married. Kinsey