Chills1994,
When my son was that age, And he did something like that I would:
Give him options, You have option A( The right Thing to do, According to me.) or option B ( What he wanted to do). You know now that he is 26 and all his friends are in jail..... He tells me " Always go with option A". I would tell him that, I wouldn't ask him a question that I didn't already know the answer to! ( IE what he now calls a" DAD question"!) If that doesn't work mix both boxes of cereal!!!
Ivan