Here are a couple panels from a rather bizarre story in Action #289. Supergirl decides to play cupid for Superman in this story, but each time she sets Superman up with a gal, something goes wrong. Finally she confesses, and Superman lets us know where Krypton stands on cousins marrying.
Note: You can always click on a picture here to see a larger version.
Although generally a model of propriety, DC did a couple of really weird ones where you gotta wonder sometimes what they were thinking--did an artist pull one over on them? Check out the cover on this one:
We all know what kind of super-feats she has in mind. And yes, Lois, it certainly looks like Superman's excited, and covering it up with the Daily Planet.