He's getting smart now and knows how and when to lie. Once again a completely normal behavior but oh so annoying. At this point his lies are completely obvious so it's funny.
One other issue is using naughty words. All of a sudden he thinks it's hilarious to say things like "poo poos", or "shit", or "stupid". Then the most fun part of parenting comes in...disagreeing with the other parent on how to handle the situation. Dad yells and says "don't let me hear you say that again!" Super effective (rolls eyes). I go between ignoring it and offering a different word to say instead. That does work to some extent but I think it's Madison's reaction that he really gets a kick out of. She ALWAYS runs to us "Jackson said stupid"! No matter how many times I tell her to ignore him she won't listen. She's such a rat!