I have a little guy who is almost three and he is a toucher too! It doesn't bother me if he is just touching my arm or leg, but he often tries to put his hand on my back under my shirt and I always remove it and ask him not to as I think this is going too far (if it were my own child it would be fine). He sometimes tries to do the same thing with the other kids and if they aren't in the mood, they tell him and if he doesn't stop I tell him "so and so has said 'no' and that he means he doesn't like it, you have to stop"....he is learning...it takes time and reinforcement. As someone else said, this is his way of showing affection.