Nobuku and her darling at a love hotel?

I would have sworn that I read in the manga somewhere that Risa and Otani run into Nobuku and Nakao coming out of a love hotel (after graduation). Risa is shocked, and Nobuku kind of gives her a wink and says something like "We can't stay children forever."

Am I hallucinating, or does that scene happen in the post-graduation manga at some point? I know it's implied in the "Maity and Jody wedding" story that they sleep together, but that's not what I'm thinking of.