Green’s Dictionary of Slang

a euph. for shit v. or bugger v.¹ in various uses.

1888–94		‘Walter’ My Secret Life (1966) VI 1149: Ah, I’m older, but sugar me if you go yet.
1898		Binstead & Wells Pink ’Un and Pelican 206: Oh — er — sugar the s’ntries, le’m take a run.
1903		A. Binstead Pitcher in Paradise 7: I don’t refer to the papers, they can go and sugar themselves.
1905		L.C. Cornford Canker at the Heart 3: ‘Bloomin’ fine thing,’ I says, ‘to be sugared about like this.’.
1946		G. Gibson Enemy Coast Ahead (1955) 265: I said ‘Sugar off,’ and told him to do something very difficult to himself.