I am new to the forum and will do an intro but to answer this question, I think it stems back to our mothers or whoever raised you telling us that masterbation is bad. I think most of us guys are brainwashed this enough that the guilt never leaves us. Even my own father said that if I did it enough, i would not be able to have good ejaculations when i am older. Well, now I am older and that has proved out not to be true.