Samantha's Witchcraft Blows a Fuse - S8-E25
Continuity mistake: The hole (square cut out) is visible in the carpet before they fall through. Also, when Dr. Bombay "cures" Samantha and she floats, the hole in the floor beside the couch is gone. Dr. Bombay fixed the floor in the next shot (when asked). The floor without the hole is visible when Dam floats up and when Darrin and Bombay walk over to her.
Answer: Larry had been telling Darrin what it means psychologically that Samantha gave the coat away. Larry said giving it away meant she's happy being married but if she liked the coat it means she desires to be single and carefree. So when Darrin sees the coat, he immediately thinks Samantha doesn't want to be married and the fact that she twitched it means (in his mind) she wants to be a single, carefree witch again.
Bishop73