Baby, baby...

I was wondering if anyone could explain this old childhood rhyme to me:

Baby, baby,
stick your head in gravy
wash it out with bubblegum
and send it to the navy

I'm an adult now and I STILL don't get it. I tried looking it up online and found not only "my" version, but also some versions with "wrap it up with bubblegum" for the third line or "and now you're in the navy" for the last line. I didn't find anything explaining what it means, though.

Anyone who tells you the underlying deep meaning of this epic bit of masterful poetry is likely a liar, liar, pants on fire, hanging from a telephone wire or else a nanny-nanny boo-boo stick your head in doo-doo.
Neener neener neener. (^_^)