Great tune!
The lyrics and chords of this and several other Snock songs have been submitted by fans and posted in the 'Discussion' section of Hurley's Facebook group -
http://www.facebook.com/group.php?gid=10596896659&v=app_2373072738

Still not sure who wrote it - thanks, Mudcatters! - but
I do it as written there -- Am - G - Dm - Am over and over ...

Peter Stampfel also covers it... on 'Goobers - A Collection Of Kids Songs,' 1993.