Guys, I too have been going crazy with this song over the years. My mother sang it when I was young. Even as I obtained the enlightenment of adulthood, she would stop and hum the rest driving me batty. I would poke and prod her but to no avail. I also heard it on MASH sung by Col Potter in shower. This is how my mother sang it...

I love to go swimming with bowlegged women
and dive between their legs,
they're round in the middle and shaped like a fiddle....

and of course this is where she would always stop telling me it's much to dirty to finish. Thanks Mom.