A single twisted, knotted mat of hair protruding from the side of a woman's head obtained when the man she has just finished giving oral sex to has ejaculated into her scalp then quickly rubbed it in with his hands (in the hand-warming motion of rubbing them together quickly).
If performed correctly, the result is permanent and can only be removed by cutting off the entire Dreadlock with scissors. It may or may not be kept as a trophy by the man.
"Yo, remember that bitch that shot me down at the Senior Prom, back in the day?"
"Yeah, she's still pretty hot these days. And she's still a bitch, yo."
"Yo, I saw her at the bar last night, got her drunk, took her home and gave that bitch a Nut Dreadlock! I got it hangin' from my rearview mirror, yo!"