This video is kind of hard to hear, but basically it's Jonah imitating Matt sticking his tongue in and out and making a funny noise. Obviously Jonah can't make the noise, but he's trying really hard to imitate the action. This is the one thing that makes Jonah laugh out loud. He won't do it often, but when he does, it's because Matt is doing this. I didn't catch any laughs on camera, but did get some really good smiles.