Deep throating is a form of oral sex, a type of fellatio in which the whole erect penis is taken into the mouth, (sometimes including the scrotum as well).

Since the average erect penis is longer than the average mouth is deep, this requires suppressing the gag reflex in order to partially swallow the end of the penis.

In order to perform this form of fellatio one must relax all the muscles at the back of one's throat while gradually inserting the erect penis into the throat. It is usually helpful to have a willing, patient, partner while attempting to deep throat him or her. Deep throating may facilitate swallowing of the semen, since it bypasses most of the tongue and tastebuds.

Deep throating was featured in the 1972 movie of the same name; see: Deep Throat (movie).