nah man that's a load of horseshit for the most part, unless you have a porn / masturbation addiction which is otherwise impacting your life. In fact, conventional science suggests that masturbation is a great natural method of stress relief. Myself, along with many close friends have tried it, and we didn't notice any sort of massive improvements, apart from one friend who developed an addiction to the stuff. But of course, everyone responds differently, please feel free to try it if you feel it will help you, it seemed to benefit a friend of mine who also stutters slightly. I'm currently trying SSRIs for anxiety, but no major improvements thus far. We shall see.