Here's how I remember it-

We are the night shit shifters
We shift shit by nigh-i-i-ght

Hitler- he's only got one ball
Goering- has two but very small
Himmler- has something similar
But poor old Goebbels (Goeballs), has no balls, at all

I've just looked in "Kiss Me Goodnight, Sergeant Major" (Martin Page- 1973)where there are three pages devoted to the origins of this song. It seems that Martin wrote to 'The New Statesman' after the Russian autopsy results were published asking how the author of the song could have known of Hitler's deficiancy. This became the subject of an intense, scholarly and lengthy debate conducted through the paper's correspondence columns through the spring of 1973.