The One After the Superbowl, part 1 - S2-E12
Continuity mistake: When 'Drake' is having dinner with Erica (the stalker), Joey is seen to be wearing a ring on the ring finger of his left hand. This can been seen just before another diner begins to choke. When the episode cuts back to them in the restaurant, the ring is gone. (00:09:50)
The One After the Superbowl, part 1 - S2-E12
Continuity mistake: When Phoebe gets the kids to sing along to 'That's another thing that you don't wanna do', there is a little boy and girl sitting perfectly still. The shot cuts to a close-up, and one of them is now standing and they are both swaying. (00:11:40)
The One After the Superbowl, part 1 - S2-E12
Continuity mistake: Brooke Shields throws water at Joey, and he gets a large spot of water on his shirt, but in the next shot the spot is much larger than before. (00:15:55 - 00:16:55)
The One After the Superbowl, part 1 - S2-E12
Continuity mistake: The first time Phoebe performs at the library this takes place at the same time Joey is on his date. During Joey's date, it's night time. But, when Phoebe is singing, it's broad daylight outside. (00:07:20)
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