Do you stutter in your mind?

Do you stutter in your mind? The other day I was reading a book, I did not stutter. At one moment I started making up a situation in my mind and I started stuttering. The situation was reading out of loud with a group of friends. Do you know why is this? I know that the stutter changes depending in the situation, but in our mind, where I don't stutter at all, is very rare. Do you think that if we change our vision situation we can cure out stuttering?