Oral

    Oral sex, known as fellatio when performed on a man and cunnilingus when performed on a female, is a sexual activity involving the stimulation of the genitalia by the use of the mouth. People may engage in oral sex as part of foreplay before or following sexual intercourse. It may also be performed for its own sake. Manga and doujinshi with this tag will contain a substantial amount of oral sex.

    Source: Wikipedia