Wow, no one has mentioned the Mary Ellen Carter yet.

Let's see, how does the story go? Think of Mary Ellen Carter as a very large hooker. Some sailors take her up on her solicitations one stormy night and after much drinking they all go out into the alley. Poor Mary has trouble keeping her balance in her advanced state of inebriation and falls down a lot. The equally drunken sailors spend their time trying to get her up and having their way with her.

With a little imagination and keeping an eye open for double entendres you may find you have trouble singing this song with a straight face.