Wait- OMG! The song is really about...?

Metallica, ’Enter Sandman’,

....is about crib death.

Source: the making of Metallica’s Black Album, 1 hour documentary, ’classic albums’ series - direct question, direct answer from James Hetfield. (with explanation)

Very sad

The Song Closing Time by Semisonic is not about when the bars close, but about pregnancy.

"Mercy, Mercy, Me" is about overpopulation and environmental collapse. 

Every time I hear "Santa Baby" in a shopping mall at Christmas, I wonder if people pay any attention to lyrics.  It is sung by someone offering sex for all sorts of material things from "Santa" with each stanza ending with "hurry down my chimney tonight;" anyone needs more than one guess as to what that means?

Melanie's song about rollerskates and a "Brand New Key" is a little bit more subtle, but the same subject.

Finally, I like the idea of the opposite--an innocent meaning to something that seems obviously not.  There is an obvious meaning to the Starland Vocal Band's "Afternoon Delight."  But the group insisted (probably falsely) that the reference is to the Happy Hour menu at the restaurant "Clydes" which is a local Washington DC area establishment (where the group comes from).