Knuckle Touch

Okay, there's this kid that I know named Jacob. We have science and Gateway to Technology (an electronics class) together. Well any time that I speak up in class and let my brain show, and get something right in class, he always reaches over and goes,"Knuckle touch," or ,"Pound it," and it's a little annoying especially considering I don't really even know what it means. I mean, I have a vauge idea, but I'm not totally sure. Annoying huh? Also he only does this to me as far as I am aware.