The logical response to being called a motherfucker. Being called "motherfucker" implies that you fuck your own mother and is generally considered the highest insult one can bestow.
By immediately responding "dadshagger" one temporarily confuses one's literary opponent as to whether it would be worse to shag their dad or fuck their mother and whether they have in fact been semantically bested. Erstwhile, thou positions thine foot squarely betwixt their thighs with such vehemence as to render them infertile for the rest of their sorry ass life.
Antagonist: "You motherfucker!"
Pacifist: "Dad shagger"
a person who shags fathers (dad's) the opposite of a mother fucker
man that dad shaggers done it again,
you fuckin dad shagger pick that fuckin shit up,
i known you've been dad shagging you fuckin dad shagger thats why you smell of shit