To sway one’s head with extremely exaggerated motions of the neck, usually while waving one’s finger and talking with lots of niggerspeak. Almost exclusively done by female niggers, hence the term.
Nigger: “What now don’t you get tryin’ to pull dat shit whit me boy! You know I aint-no-bitch! What you get yo damn ass back here!”
God damn, that bitch was niggernecking me…