English Department Defeats Google . . . In Bed?

The other day I was racking my brain because I knew there was some situation where you insert the phrase "in bed" at the end of a sentence, for humorous effect, but I couldn't remember when you did this (and I was kind of mixing it up with Michael Scott's catch phrase "that's what she said") and I Googled it and it didn't come up so I thought I was losing my mind and that maybe I fabricated this idea and it was not a thing in the reality of our known universe but during lunch I asked my fellow English teachers and they said this was what you did with the little nugget of wisdom inside a fortune cookie and I was like "yes!" and I have no idea where this tradition originates but that's what I was thinking about-- "you will never hesitate to tackle the most difficult problems . . . in bed."