Who Writes the Lyrics?

I was doing some reloading this evening after it was too dark to split wood. As I listened to the radio while working, I’m thinking, who writes these lyrics?

One song, by Elvis Costello, I think, goes,
"Allison, my anus too…" What the hell is that supposed to mean?

Then another, by the Four Tops (?),
"Ain’t no woman like a one eyed slut…"

Those songwriters need to get a grip.