I worked with DD adults in a behavioral day program and have a pretty darn good idea of what you are going thru! Does your son have a TBS worker? TBS stands for Theraputic Behavior Specialist. They are social workers who work one-on-one with a client (child or adult) on behavioral issues. Since your son is autistic he will have behavioral issues his entire life, they will change but there will always be something. If he doesn't already have a TBS worker look into getting one (contact the county, they usually provide this service for free or very low cost), they can help both of you a lot. Another thing I found with the clients I worked with, many of whom had not received very much treatment, some were in their 40's and older so they were simply warehoused for most of their lives. Anyway, they didn't have the skills to express emotions and would act out in various ways insted, usually negatively. I worked a ton on teaching them the words for emotions and how to use them. I also found some baby sign language flash cards with emotions on them. This worked wonders. Some had an easier time with signing their feelings rather than speaking them. I think I found them at Barnes & Noble. I found the best way to prevent an incident was to watch for signs, when they were beginning to become agitated, and intervene then. Have him talk about his emotions and help him put it into words. Then talk about how to handle these emotions. Working with DD people (kids and adults) requires a LOT of talking, about half of what you say gets thru, so talk, talk, talk. Good luck and hang in there!!!