Cunnilingus is an oral sex act performed by a person on the vulva or vagina of another person. The clitoris is the most sexually sensitive part of the human female genitalia, and its stimulation may result in a woman becoming sexually aroused or achieving orgasm.
Cunnilingus can be sexually arousing for participants and may be performed by a sexual partner as foreplay to incite sexual arousal before other sexual activities (such as vaginal or anal intercourse) or as an erotic and physically intimate act on its own. Cunnilingus can be a risk for contracting sexually transmitted infections (STIs), but 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, but most countries do not have laws which ban the practice. Commonly, heterosexual couples do not regard cunnilingus as affecting the virginity of either partner, while lesbian couples commonly do regard it as a form of virginity loss. People may also have negative feelings or sexual inhibitions about giving or receiving cunnilingus or may refuse to engage in it.