Iv been finding it harder lately to refrain from responding to my almost step brother so i thought id take a page out of The Big Bang theory and use positive, perhaps negative reinforcement. Anyway i was looking for some suggestions for what to use. He is 9 years old. The conditions are he cannot eat artificial additives, i want it to be subtle and something he wont make a big deal of, and i would rather my dad and his mum not know about it.