Fellatio (also known as fellation, and in slang as blowjob, BJ, giving head, or sucking off) is an oral sex act consisting of the stimulation of a penis by using the mouth. Oral stimulation of the scrotum may also be termed fellatio, or colloquially as teabagging.
It may be performed by a sexual partner as foreplay before other sexual activities, such as vaginal or anal intercourse, or as an erotic and physically intimate act of its own. Fellatio creates a risk of contracting sexually transmitted infections (STIs), but the risk is significantly lower than that of vaginal or anal sex, especially for HIV transmission.