The One With The Screamer - S3-E22
Continuity mistake: After the play, Joey asks Kate how she is doing, and she says "fabulous". She brings a cup to her mouth, and then does it again from another direction. (00:09:30)
The One With The Screamer - S3-E22
Continuity mistake: When Tommy starts shouting at the duck it changes its position. (00:15:15 - 00:18:00)
The One With The Screamer - S3-E22
Continuity mistake: When Gunther brings Chandler the cup of coffee from the woman at the bar, Chandler does not take it by the handle; however the shot quickly switches to him holding it by the handle. (00:14:00)
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