Green’s Dictionary of Slang

(N.Z. prison) one who is ‘above average’ (i.e. 50%).

2001

D. Looser Boobslang [U. Canterbury D.Phil. thesis] 167/2: sixty-center n. a person deemed worthy to converse with, better than average in terms of his character and behaviour.

a sexual athlete, one who can postpone his orgasm for sixty minutes; thus dimin. sixty-minute boy.

1950		Billy Ward & the Dominoes ‘Sixty Minute Man’ 🎵 Looky here girls I’m telling you now / They call me Lovin’ Dan. / I rock ’em, roll ’em all night long, / I’m a sixty minute man.
1980		Spoonie Gee ‘Spoon’nin Rap’’ 🎵 I’m known from coast to coast as the sixty-minute man.
2002		D.H. Sterry Chicken (2003) 34: Suddenly the sixty-minute boy is back on the job.

a money-lender, a usurer, a bill-discounter.

1853		C. Reade Gold i I n.p.: What you do on the sly, I do on the sly, old sixty per cent [F&H].
1864, 1867, 1870		Hotten Sl. Dict. 232: SIXTY-PER-CENT, a bill discounter.
1891		F.W. Carew Autobiog. of a Gipsey 228: A Gentile sixty-per-center named Ben Davis.
1897		R. Marsh Crime and the Criminal 89: Was he going to develop into a sixty per cent, and offer me a loan?

(US black) a premature ejaculator.

1974

D. Goines Daddy Cool (1997) 120: Shit, man, you talkin’ ’bout a sixty-second man. You wasn’t on that cock a minute.

(US) cheap, probably harmful whisky.

1880

Hartford Herald (KY) 17 Mar. 3/3: He keeps no fusil oil, bust skull, sixty yards, rifle whisky, but he has the pure article.