Couple & Koi

GF: Look at these fishes. They're so big. And there are so many of them.
BF: Koi's what they're called.
GF: As in King Coil the mattress?
BF: As in we'll be sleeping on different mattresses when...correction, IF we get married.
GF: Why?
BF: Because I can't really see myself growing old with an ignoramus. I'd rather rear a guppy.
GF: But what's that gotta do with mattresses?
BF: ...