Since Lexi was born I've made a big deal about Addison helping.  When she brings me a diaper or a pacifier I'll tell her what a good helper she is.  Sometimes she helps me pat Lexi's back when I'm burping her and says "I'm helping".  She has even put her hand on the back of Lexi's head while I'm nursing and says "I'm helping" lol.  Last month the maintenance guy was here fixing things and at one point he was squatting to fix something and Addison put her hand on his shoulder and said "I'm helping" lol.