The One Where Joey Dates Rachel - S8-E12
Visible crew/equipment: When Ross is wearing roller-blades while teaching his class, just as he points to the map and says, "Here," the second time, there's a hidden crew member that can be seen behind the end of the set wall with the map, at the left side of the screen.
The One Where Joey Dates Rachel - S8-E12
Visible crew/equipment: As Ross enters the classroom for his second lesson, he bursts in and for roughly five seconds, a boom mic is visible hovering overhead near the door. (00:10:15)
The One Where Joey Dates Rachel - S8-E12
Visible crew/equipment: In the scene of the classroom, before Ross faints, he says, "Why don't you all" and above his head near the clock, there is a boom mic. (00:18:50)
Answer: The statements that she's contradicting (that it is common, it happens to every guy, and it's not a big deal), are the things that a woman commonly says to a man who is suffering from erectile difficulty, typically to assuage his bruised ego. However, most men do not believe that these statements are true, as evidenced by Chandler's outburst. He's so caught up in the proof that women are lying about it that he gives himself away.
Rooster of Doom