Two perverts find happiness in sharing their fantasies with each other - if this isn't as sweet and romantic as it gets and doesn't deserve a vanilla tag I don't know what does...
Carnal feelngs doesn't have to be considered vulgar, you know?
Still...They're both perverts, so really, I'd say they go really well together! They can try out their fantasies on each other, truly a perfect pair.
Many years later, some small children listen transfixed to an edited version of this story, even as Sakamoto and Narasaki conclude: "And that's how your mother and father first got together."