The song contains the following lyrics:

You can't tell the depth of the well by the length of the handle on the pump...
Baby... How can you tell about me?
You can tell a book by it's cover...
That's how it is with me.
I'm an under cover lover...
Give me a chance and you'll see...

Hope that's enough.

I believe it's "The Pump Song" By The Honkin’ Hep Cats.