I'm already getting so protective. My nephew is almost 2 and I'm lying on the couch and he walks…

I'm already getting so protective. My nephew is almost 2 and I'm lying on the couch and he walks over and head butts me twice right in the stomach. My first instinct was to smack his butt and tell him no, but I know he doesn't know any better and was just playing with me. My baby boy kicked back real big too! He's not gonna let his cousin bully him!