We hardly ever use the word "NO" unless if he is doing something really bad. We say "HEY" or "DROP IT" or "STOP IT" and he knows. If he has something in his mouth and we say "DROP IT" and he does we tell him "THANK YOU" and pat his head and say "GOOD BOY"!!! It seams to work. We tell him "THANK YOU" alot after we "repremand him".
Mandy & Luigi