M.C.
As a teacher I have worked with some autistic boys around your sons age however they were not blind. We work with the boys to keep their hands out of their pants which begins the stimulation process. We remind them constantly to have "quiet hands" translation: take your hands quietly our of your pants. In a non verbal communication you might be able to touch his hands before he puts them in his pants and however you use to communicate "no" do so at that time or even as he has just placed them in his pants. I am assuming that this is how he stimulates himself to the point of ejaculation. I hope I have assummed correctly and this will help some. Bless you for continuing to work with your son as autism is frustrating in andof itself let alone adding another disability. I admire you and honor you for the work you and your family are doing.