This might be elementary to some of you, but what is the "blooper" in the dance episode everybody's referring to? What happened?

it is a dance in the blooper episode

What?? Please clarify. From what I gather, there was a "blooper" (mistake, goof, etc.) in the episode where they did the dance. If so, what was the blooper??

its a dance they did in the blooper episode.....your reading my post dyslexicly