I've searched Mudcat and Google for this song to no avail. It's a comedy song by a woman folksinger and it includes some spoken material. The gist is that if PMS really does make women mean and volatile, then Marine recruiters should favor women over men. The women Marines should bunk together so that they synch up and they should be first on the beach every time, since you want the meanest toughest you-know-whats to lead the charge. The chorus is a cadence that goes like this:

You may laugh
And you may jest,
But don't you mess
With a woman with PMS!