Learn English – What does zitch dog mean

Something like: dingbat, thingamabob or thingy .

From

1925 E. FRASER & J. GIBBONS Soldier & Sailor Words 215 Oojah (also Ooja-ka-pivi), a substitute expression for anything the name of which a speaker cannot momentarily think of, e.g. ‘Pass me that h-m, h-m, oojah-ka-pivi, will you?’ 1931 J. VAN DRUTEN London Wall II. ii. 73 There's a whole lot in the Oojah Capivvy now. 1962 Sunday Times 4 Feb. 31/6 This was the catch-phrase in a music-hall song in use during the first world war... I remember the line and the tune: ‘You cannot eat it, or see it, or hear it, you just ask for Ujah-ka-piv.’ 1966 ‘L. LANE’ ABZ of Scouse 78 Whur's ther ojah-capiff?, where is the hammer, spanner or whatever it might be? 1992 Hobart Mercury 8 Aug., There are several of Ms Bosanky's turns of phrase that are pure Downunder. For instance, ‘hoojah-kapippy’..or a ‘whatsitsname’ euphemism.

Found a little history on the word. It is indeed Yiddish:

shprits
spurt, to squirt, to sprinkle ∙ (m.) שפּריץ

Neal Karlen in The Story of Yiddish: How a Mish-Mosh of Languages Saved the Jews, says the word took on new meanings within a community of young Jewish comedians (exemplified by Lenny Bruce) in New York in the 1940s:

Using Yiddish as a base, the young Jewish comics helped develop only the second art form indigenous to the United States: the shpritz, a.k.a. "Jewish jazz." (African-American jazz is often thought of as the only such legitimate claimant. Curiously, "jazz" is slang for ejaculate: shpritz is Yiddish for "spray." Talk amongst yourselves.)

Wikipedia has this description from Albert Goldman of Lenny Bruce "shpritzing" during a famous Carnegie Hall concert:

Lenny worshipped the gods of Spontaneity, Candor and Free Association. He fancied himself an oral jazzman. His ideal was to walk out there like Charlie Parker, take that mike in his hand like a horn and blow, blow, blow everything that came into his head just as it came into his head with nothing censored, nothing translated, nothing mediated, until he was pure mind, pure head sending out brainwaves like radio waves into the heads of every man and woman seated in that vast hall.

Because of the word's historical association with Jewish comedy, its use in the quote you found is quite appropriate and well-chosen—even if a bit esoteric.