I read about it a couple of decades ago—not sure of the history of the term.
Given extreme Internet censorship it is hard to get accurate history of the manosphere.
I would advise young men to never ask that question.
The old advice to trial lawyers applies: If you do not already know the answer then do not ask the question.
The reason—information the woman gives is impossible to evaluate—and most certainly should never be taken at face value.
If she brings up the subject and volunteers just nod and listen—just like if she was telling you that she calculated the number of angels on the head of a pin.
:-)
A guy could tell a woman he could count on one hand how many women he’s been with, the woman would either lie, or get pissed you were judging her as it’s unlikely she could say the same thing.