Green’s Dictionary of Slang

mammy-tapper n.

(US black) euph. for motherfucker n.

1967

A. Baraka Tales (1969) 18: You talking about a lightweight mammy-tapper, boy.

In derivatives

mammy-tapping (adj.)

euph. for motherfucking adj.

1962

(con. 1950s) H. Simmons Man Walking On Eggshells 204: Can you imagine a stud like me, who used to be one of the baddest mammy-tapping gangleaders in this jive town, now trying to uphold the law?