Lyric discussion by Sir_Larrikin 

Cover art for Thunderbird lyrics by They Might Be Giants

To me, I think this song is about the cheap wine that you can buy for a couple bucks. This song would be what a bum would sing, with his wine in a brown paper bag. Perhaps about alcoholism -- the part about crawling before falling, for instance, is probably making a reference to drunks needing to bottom-out before they can get better (before they realize that they need help).

Fun Fun Fun is a ref, obviously, to the Beach Boys - not sure why, though.