Green’s Dictionary of Slang

used derog., despicable.

c.1930		N. Kimball Amer. Madam (1981) 318: Harry called him a muff-diving greaseball cocksucker.
1952		(con. 1920s) ‘Harry Grey’ Hoods (1953) 356: ‘You muff divin’, stinkin bitch [...]’ I spit on him.
1969		P. Roth Portnoy’s Complaint 118: You muff-diving, mother-fucking son of a bitch!
1979		D. Maitland Breaking Out 169: You are a bloody lop-eared [...] muff-diving, mickey-munching [...] fart-faced flip of a fucking galah!
1981		S. King Cujo (1982) 42: They were all a bunch of long-haired, muff-diving [...] pinko fucksticks.
2001		‘Randy Everhard’ Tattoo of a Naked Lady 158: I aimed to fuck my way clear through her muff-diving mouth.