Take it from me - being an authentic, absolute cum slut require both mental and physical attributes that are difficult if not impossible to teach. You are just born with that ability. For example, the innate compulsion and desire to automatically fall to one's knees and begin sucking whenever in the company of an erect cock can't be taught - it's in one's genes.
Just think about it. You've seen books on the shelf for just about every subject. Such as "Accounting 101". Have you ever seen a book entitled "Cumsluts for Dummies"? No! The reason is because the subject can't be learned. It's just part of who I am. I wish I could teach it to someone. I could make thousands of $$ making instructional YouTube videos on the subject. Ever wondered why there are none of those videos on YouTube? That's why
Sorry....