A popular phrase used to point out a double entendre is "That's what she said!" For example, when speaking of moving a couch: "It was huge, and took forever to get inside." "That's what she said!".

I've never really thought about the origin of many sayings but decided the one that I probably over use is "That's what she said." So I dug a little deeper. Among its usage on many television shows, it has been widely known for years as a playoff of two men discussing their sexual conquests with a cleverly laid out "That's what she said" joke. This joke's origin is unknown but the first known documented usage is from the movie "Wayne's World." In the scene Garth is holding a large picture of Claudia Schiffer. Garth tells Wayne, "Are you through yet? I'm getting tired of holding this." Wayne responds, "Yeah, that's what she said." The phrase is also used quite often by the character Michael Scott on the U.S. version of the TV show The Office.