The One With The Vows - S7-E21
Continuity mistake: After Monica says "Oooh can we lie in our vows?" it cuts to Rachel then back to Monica leaning on her hands, but when it goes for a close up she is holding the pen in her right hand, there isn't enough time for her to naturally pick it up. (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