I am not talking about proper Spanish, because this word with this meaning is not proper, it is vulgar slang in several countries.
I didn't mention any books either. I support my statement as a Spanish speaker and in my 24 years of experience as a profesional translator who has travelled extensively and corresponded with Spanish speakers form many areas of the world.
I just answered a question, I tried to help. You are free to insist on any wrong idea with farfetched reasons. I am not going to argue with you.
Have a nice weekend.