The One With The 'Cuffs - S4-E3
Visible crew/equipment: At the end, when Rachel walks into Joanna's office to find her handcuffed to the chair, the camera can be seen in front of the filing cabinet, at the right side of the screen.
The One With The 'Cuffs - S4-E3
Continuity mistake: The handcuffs that Joanna uses on Chandler have a single metal bar connected via pivot to a double bar with the lock area. When Joanna first cuffs Chandler, the double bars on both sides face up at his wrists, but when Chandler's on the phone and when Rachel unlocks his right cuff, the handcuffs are going round his wrist the opposite way with the single bars facing up - quite impossible. Then the same thing occurs when Rachel handcuffs Chandler to the filing cabinet.
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