Green’s Dictionary of Slang

futhermucker n.

(US) a joc. reverse of motherfucker n.

[US] oral testimony in Lighter HDAS I.
[US]R.A. Wilson Playboy’s Book of Forbidden Words 171: Motherfucker. [...] various timid, euphemistic or quasi-humorous variations such as [...] futher-mucker.
‘Whinge’ 2 Dec. at 🌐 Jesus Christ, music is a moving futhermucker. Plus, I really need some sleep.