Tantrums anyone?

Kyle is a very smart little boy. He can understand everything I say and he can certainly express himself very well. And lately he has no problem basically telling me to go jump in a lake too! What the heck!? Not literally, but he is strong with telling me NO he doesn't want to do something, with resorts to naughty seat, which becomes Mom holding him in said naughty seat and usually ends with him giving me a good slap. My shock turns to losing his grip, he's off and running and I am deflated, defeated sitting in the naughty seat (not coincidently I assume). After the crying stops I can usually get a "Sorry Mommy" out of him after I can explain why he went to the naughty seat. And I try my hardest to stay strong, be stearn, not flip out but somedays I just don't have the energy to fight with a 20 month old. I really need some TLC...........