Green’s Dictionary of Slang

1. (Aus.) excellent, first-rate, a good deal, e.g. curl-the-mo mazuma, a great deal of money; also as v. to do very well (see cite Truth 1944) and excl.

1938		Williamstown Chron. (Vic.) 26 Nov. 2/2: As long as we don’t interfere with Geordie’s dock everything is ‘curl-the-mo’.
1941		Baker Popular Dict. Aus. Sl. 42: Kurl Good, excellent. Also, ‘kurl-a-mo’.
1944		T. Hartley glossary in Simes DAUS (1993) 61/1: curl the mo First rate, excellent. Usually accompanied by imitating the action of curling a moustache with the thumb and forefinger, as though one were accepting applause.
1944		Truth (Sydney) 13 Feb. 4/3: One of the chief cat-whippers in Melbourne today must be Scobie Breasley [...] Breasley saw Kintore donkey-lick a field of youngsters in the Federal Stakes, and had salt rubbed into his wound when the Lewis cuddy Valour curled the mo in the Bond Handicap.
[1945		Baker Aus. Lang. 126: Curl-the-mo was apparently first used to denote the self-satisfaction of a man who twirled the ends of his flowing moustache. It was then applied to anything meriting approval, was shortened to curl. [...] A popular song ‘Curl-the-Mo, Uncle Joe’ [was] written in praise of Joseph Stalin, who has a large moustache].
1948		S.L. Elliott Rusty Bugles I i: The Blue Orchids are curl the Mo.
1953		T.A.G. Hungerford Riverslake 119: ‘Roddy was in the air force’, Spain announced [...] He looked at Randolph and grinned. ‘Curl the mo!’.
1962		Central N.J. Home News (New Brunswick, NJ) 1 July 1/6-7: [Aus. speaker] If only people here spoke [...] clearly, she’d be curl [...] curl (curl a mo) — Excellent.
1977		S.L. Elliott Water under Bridge 313: Maybe I’ll look very curl-the-mo in my uniform, eh? [AND].
1982		G. Newbold Big Huey 247: CURLY MO (adj or adv) All right, fine, go ahead. Rhyming slang for ‘A great go.’.
2004		posting at www.catzooks.com 15 Sept. 🌐 If you thunk the forestay fitting is good, wait till you see these beauties. As we say, curl-the-mo.

2. self-satisfied.

1967		K. Tennant Tell Morning This 206: Old Curl the Mo had complained to a felow warder about Chigger lounging, smoking.
1968		(con. 1928) S. Gore Holy Smoke 91: Yair, real curl the mo’, that joker.