When a girl is giving a guy a blowjob and the guy puts most of his dick into the girls mouth. The dick touches the throat, and often makes girls gag.

1) to perform fellatio (dick-sucking) to where the penis is sticking in the performer's throat (usually causing a gag reflex);
2) title of a movie that referred to the act of deep throating;
3) name given to an informant figure who spoke to Woodward and Bernstein during the Washington Post's investigation of the Watergate break-in. His identity has essentially been kept a secret and has been the focus of a parlor guessing game in DC.
Some believe Deep Throat was either fake, a literary creation to sell the book 'All the President's Men,' but too much surrounding evidence does suggest there was at least one deep source providing clues. The more likely scenario is that Deep Throat is indeed a merging of a handful of sources (despite Woodward's assertions it's only one person) in order to both protect their identities as well as create a mesmerizing character in the book written about the investigation.
If Deep Throat is indeed one person, the most likely suspects are with the FBI, who were being pressured by the CIA (acting on Nixon's orders, according to his own tape recordings) to cover up the whole mess, and who were fighting back as best they could against a White House that was threatening their relative independence within the government (during Hoover's lifetime, the FBI became a separate power unto itself, and with Hoover's death at the time of the break-in, that was being threatened).

When A guy stick's his penis way deep in another person's throat.

The best fucking skill ever!

shoving your peins all the way in during a blowjob, so it goes into the girls throat.

to deepthroat is to take a guys dick (depending on its size, cuz even while deepthroatin some guys dont make it to the back of ur throat) and shove it all the way into the back of your throat-but only expirienced girls should try this because it can make you gag or even throw up.

When a woman takes the entire man's cock into her mouth when giving a blowjob. This can tickle the tonsils and even induce vomiting.