Green’s Dictionary of Slang

(US, mainly Southwest) euph. for motherfucker n.; thus maw-dicking adj.

1972		R. Kahn Boys of Summer 122: Dick Williams, who reasoned that he would be thrown off the bench for calling an umpire ‘motherfucker,’ cogitated and found a solution. ‘Hey,’ he’d shout. ‘Ump. You’re a mawdicker.’.
1984		(con. 1950s) A. Sample Racehoss 145: Why you Gotdam impudent shit-colored mawdicker. [Ibid.] (con. 1960s) 202: I oughta throw yore mawdickin ass in the pisser.