Oral sex , sometimes referred to as oral intercourse , is sexual activity involving the stimulation of the genitalia of a person by another person using the mouth including the lips, tongue, or teeth and the throat. Cunnilingus is oral sex performed on the vulva or vagina , while fellatio is oral sex performed on the penis. Oral sex may be performed as foreplay to incite sexual arousal before other sexual activities such as vaginal or anal intercourse , [1] [3] or as an erotic and physically intimate act in its own right. However, the transmission risk for oral sex, especially HIV transmission, is significantly lower than for vaginal or anal sex. Oral sex is often regarded as taboo , [1] but most countries do not have laws which ban the practice. Commonly, people do not regard oral sex as affecting the virginity of either partner, though opinions on the matter vary.