The One With Five Steaks and an Eggplant - S2-E5
Visible crew/equipment: In the part where Ross is on the phone with Julie he says "Say hi to Julie in New Mexico." When everyone is shouting "Hi Julie" look above their heads and you will see a boom mic dip into the shot. (00:03:10)
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