One of my alltime faves is from PPM's "I Dig Rock and Roll Music"

"And if I really say it,
The radio won't play it,
Unless I lay it
Between the lines."!

Not exactly what I think is being asked for, but a nice "got one over on 'em" methinks. Wonder how many DJs figured it out.

I am not sure if it has seen airplay, but the song "Steggie" is pretty right out there:

"He put in his steggie so plump and fat (wooo),
Then he pulled it out like a half-drowned rat
(And you know very well what I mean-o"

Indeed we do.