I am quite charmed by this. I recently came across a report in the Manchester Guardian of March 4, 1865, describing camp activities in the Federal army. It included the lovely detail that the sutler’s tent was also called a “shebang.” This recalled to my mind that my father, who was a career US Navy chaplain, called the navy’s rough equivalent a “gedunk.” This made my wonder about the origin of that word.
This has been mostly worked out in the Historical Dictionary of American Slang. It comes from the comic strip “Harold Teen” that ran from 1919 to 1959. Harold spent much of his time at the Sugar Bowl soda shop eating “Gedunk sundaes.” This transferred to ice cream or other sweet snacks, and from there to where you obtained them.
The dictionary leaves open what was the source of “gedunk” in the comic strip. I think it is mock German for “dunk.” The cartoonist was Carl Frank Ludwig Ed and he went to a Lutheran college in Illinois, so I suspect he grew up with German. And then there is a letter to the editor from a reader “Gretchen” (published in the Belleville News Democrat of January 27, 1925, copied from the Chicago Tribune) complaining about the bad grammar of this vogue word and giving the proper forms. I particularly like the headline given the letter: “To Eingetunkt Is One Thing; To Gedunk Is Another.”