Sounds like your son has found a surefire way to get a reaction from mom. Some thoughts: make sure you say "no" and why the behavior is not okay in as few words as possible -- for example, "No biting. Biting hurts!" or "Off the table. Not safe!" At that age, kids will tune you out with much more of an explanation. I used time outs at that age. If he does not stay put, you can tell him you are adding time and put him back where he was supposed to be staying. He might get upset, but that's kinda the point. While he is in a time out, keep an eye on him, but do not give him attention (e.g., more explanations, sitting with him, etc.) as the extra attention will be seen as a reward. Is it possible that your son is getting more of a reaction from you with bad behavior than good? I fell into this trap. I just enjoyed the good times and then reacted verbally more to the bad things my son did. I wasn't flipping out about them or anything, so I didn't realize that there was an issue. Then I read somewhere that parents should strive to say at least five positive things about a child's behavior for every negative comment. Even things like, "Thanks for eating so neatly," or, "Thanks for chewing your food so well," or "Thanks for waiting patiently while Mommy paid for that," can really help. Kids crave attention, positive or negative. You son might just be trying to get a reaction from you, and he knows that smiling or laughing when you say no gets a reaction (as does the initial behavior). Try to follow the five-to-one rule. When you say "no" and give time-outs for the climbing/biting (if you choose to do so), say everything in as succint and matter-of-fact way as possible. Ignore the smiling or laughing after you say "no." Any other reaction will likely fuel the fire.