One who has caused you displeasure that goes beyond the derogatory words of cunt and fucker. Hence the combination of both with the "a" to make sure that the poor soul knows that this is not a form of praise.
I can't believe you drew a flacid penis on my face even though I took my shoes off, you cuntafucka.
While in a car, the act of a woman having anal sex with a gearshifter while a man or female with strap on brutually fucks her vagina.
Panfilo gingerly peered through the tinted window just as Rosa slide her muddy starfish onto the gearbox while Miguel pumped her brown taco hole finishing off the sweaty gearshift cuntfuck.