As a 3rd party, cause someone giving head to gag by forcefully shoving their head into the cock as hard as you can.
Traditionally, a twisted face is made when the maneuver is enacted.
So, anyways, I was like, I came to party, you know? Not sit around and tease, like the other prude bitches, so as this "Miss Priss" chick was barely licking this cock I grabbed her by the back of the head and Doctor Feelbad'd her, and you know what? She came around.