If you have no idea what Deep Throat means (newbie alert!) or have never tried it yourself here’s an interesting little summary from Wikipedia:
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).
Since the average erect penis is longer than the average mouth is deep, this sexual technique requires suppressing the gag reflex in order to partially swallow the end of the penis. In order to perform this form of fellatio, the penis recipient relaxes all the muscles at the back of the throat while gradually inserting the erect penis completely.
In one learning technique, the recipient of the penis lies face up on a bed, head hanging over the edge. For the recipient this is essentially an “upside down” position. For some recipients, this ensures that the throat and mouth line up, and aids penetration. However, because mouth and throat structure (as well as penis shape) vary from person to person, some recipients instead prefer an “upright” position.
Deep throating may facilitate swallowing of the semen, as the ejaculate may bypass most of the tongue and tastebuds, depending on the depth of penetration at the time of release. If the penis is held completely inside the mouth and throat as the man releases (i.e., with the recipient’s lips pressed firmly against the man’s abdomen and scrotum), the semen may be released into the stomach without the recipient having to swallow.