I friend said that years ago he read where Wilson Picket admitted it was about sex. But as far as “sex songs” go, it’s pretty lame, even for the time. Or maybe I’m just used to today’s music, where there’s no room for doubt when a song is about sex.
FtG’s 1st Law of What RocknRoll songs are about:
All RocknRoll songs are about sex. Every single one of them. Even the ones that appear to be about drugs. If they ain’t about sex, they ain’t RocknRoll.
(Note the converse is not true. Many other genres are also entirely about sex. Esp. the stuff by that Mozart guy.)
Here is what the writer, Mack Rice, has to say about the origin of the lyrics. Turns out that sometimes a car song is just a car song… 
Bullshit. It’s about sex. I mean, listen to it. It’s about sex.
Sheesh, can’t anybody listen between the lines anymore?
It’s about sex.
I seem to remember hearing somewhere that it’s about a prostitute.
Rock is such that even songs inspired by a nonsexual source wind up sounding like they’re about sex.
And this board is such that even songs inspired by a nonsexual source will be interpreted to be about sex. 
I always thought it was about a partyin’ maniac chick. Kinda drunk and loose and didn’t much give a shit about anything but having a good time.
I could be wrong.
The song is about a car. Nothing more, nothing less.
But cars, now – they’re *all * about sex. . .
But Pink Cadillac on the other hand…
Q
'Cause that’s about gay sex. (Ya see how this works?)
