I can completely relate. My 3 1/2 year old struggles with hitting in the same fashion and has for a good year or more. At this point, he understands it's wrong, but struggles with the impulse control. He is a super 'spirited' child, so it's often a struggle. However, nothing we have done has manged to eliminate this behavior completely. When he does hit, we firmly tell him 'no hitting,' 'we don't hit' or 'hitting's not okay' then typically put him in a time out to cool down. Between 2- 2 1/2 he wouldn't stay in a time out... but he can handle it now. We talk about it after, make sure there are apologies and hugs... He knows better, but again it's so reactionary for him sometimes. I've got him working on 'deep breathing' now and I do it with him to get him to calm his body down. It does seem to be helping actually, he knows if he gets angry or frustrated, he can choose to walk away and take a break (on his terms), a few deep breaths and calm down. We also stress using his words. Again, now that he is a bit older, he's learned to pretty well identify his feelings. So in your case, after the storm has passed, see if your little boy can articulate how he was feeling (sad, mad, etc. and why)... Good luck, hang in there, be consistent & persistent :)