Used to love this tune - without knowing what the hell it was all about (thought it was about lovin' our Japanese bros). Then saw the lyrics on YouTube and the penny dropped.
Check out the explanation on the YouTube comments sections. Funniest song ever? (I wonder if the Japanese ever knew?Though I suppose they must have come across the expression pasted below...)
http://www.youtube.com/watch?v=5mO4mJA3MYs
SPOILER!
...ie "Grinning like a wanking Jap"