O-Face: The facial expression one makes at the pinnacle of an orgasm. The lips are typically pursed into an "O" shape.
Plastic Surgeon: Ms. Ironbox, I am instructing you to achieve three orgasms a day for the next two weeks.
Ironbox: [blushing and angry] I beg your pardon!?!?
Plastic Surgeon: Your facial spasms and eye twitches will surely dissipate with a genuine regiment of O-face therapy.
GF: Shit! Now we're screwed! Didn't you hear me whispering: Don't! and Stop!?
BF: Umm, I heard you whispering: Don't stop! Plus, you came, and that was the reason we parked here.
GF: My minister drove past and I couldn't hide my O-face.
BF: Meh. Just tell him you were praising God.
GF: In a cemetery?!?!
And yes, this clip will make the hardest dick go limp, but Office Space made this Urban Pictionary term famous:
hxxp://www.youtube.com/watch?v=k6UPR3OdroY