flummadiddle n Also flumididdle, flumme(r)diddle, flummydiddle, fum(m)adiddle [Perh elaboration of flummery n]

See quots. NEng ?obs

1857 Harper’s New Mth. Mag. Sept 538/2 NEng, Flummadiddle is a compound mixture . . of . . stale bread, pork fat, molasses, water, cinnamon, allspice, and cloves. It is a kind of mush, baked in the oven. 1872 Schele de Vere Americanisms 338, Such is the flummadiddle, a holiday-mess of New England fishermen. . . It consists [primarily] of . . stale bread, pork-fat, molasses, cinnamon, allspice, and cloves . . baked in the oven and brought to the table hot and brown.
also attrib: Nonsense, foolishness—sometimes used as exclam.

1848 Thompson Green Mt. Boys 255 eNY, If a British General had not writ it, I should have called some of it nothing but damn flumididdle. 1854 (1923) Holmes Tempest & Sunshine 32 KY, What does she want of any more flummerdiddle notions? 1868 Brackett Farm Talk 70 NEng, What’s the use of so much ‘flummy-diddle’? Plain common sense is enough for any farmer’s paper. 1903 DN 2.297 Cape Cod MA (as of a1857), Flummydiddle. . . Foolishness. 1942 Sat. Eve. Post 25 Oct 35/3 Sth [Black], An’ does you try any fumadiddles, you is right away gwine happen to a catastrophe. 1942 in 1944 ADD [Black], [Radio:] Aw, [ˈfʌmədɪdḷ]. 1978 New Yorker 11 Sept 33/3, What kind of fumadiddles is that brat of mine mixed up in now?
A frill, bauble, bit of finery.

1882 Advance (Chicago IL) 21 Sept 605/2, Directions for . . crocheting all sorts of flummediddles. c1939 in 1944 ADD, Then, all diked out in these fancy fumadiddles, what does he do? 1948 Popular Western June 104/2 (DA), I know a California vaquero feels positively naked if he don’t have some fumadiddle about his get-up.
A doodad, thingamajig.

1897 KS Univ. Qrly. (ser B) 6.52, Doofunny: a thing not easily described, or thus mentioned to save description; . . thingumbob, . . fum-a-diddle. 1905 DN 3.66 NE, Thingumbob, . . dingus, . . fummadiddle, . . jigger, [etc]. 1931 AmSp 6.258,Indefinite names current in the Central West. . . fumadiddle.