Green’s Dictionary of Slang

mothering adj.

a euph. for motherfucking adj.

1951		J. Blake letter 21 June in Joint (1972) 21: He said if the motherin’ screw ever caught up to us, he’d wish he hadn’t.
1963		J. Rechy City of Night 299: That dirty motherin bastard, we gonna come back and git him.
1968		T. Wolfe Electric Kool-Aid Acid Test (1969) 137: Kesey [...] dives in that mothering cold water, by way of shocking himself awake.
1972		B. Rodgers Queens’ Vernacular 108: That motherin’ punk oughta be taught some manners about holdin’ his mud-he shit all over me when I shoved it in him.
2009		T. Black Gutted 6: Holy shit [...] holy mothering fuck.