Playful Germanic double entendre for:
1. 'Jude' or Jew.
2. clitoris. Based on the smaller size of the Asian Jewish Penis as compared to the North European German Penis.

The equation of the Israelite Semitic Penis with the German Klitoris is an integral part of pan-German erotic slang: "049. 1.68. Klitoris. Begeisterungsknöpfchen, Blinddarm, Bubikopf, Damendegen, Däumchen, Feigenwarze, Funzeldocht, Fut-warze, Jud, Kitzler, der Kleine, Knopf, Knöpfchen usw." ('Pornost: Triebkultur und Gewinn' Brigitte Classen. München: Raben Verlag, 1988, p 25)

It is deep-rooted in all parts of the Germanic world, right from Berlin to Austria & Styria:

"Der Jud seems to be a common name for the clitoris in different parts of the German-speaking sections of Central Europe. Kostial (14) heard it used in Styria. Reiskel (15, 16) found it in Berlin, where he also met the expression Jude Kohn, & in Vienna, where Am Jud'n spiel'n {am Juden spielen} and Den Jud'n stemma {den Juden stemmen} was used to mean 'fellare vel irrumare clitorem' {active fellation & receptive irrumati...