How does our dog Buster always surprise me like this?

I've never met a dog like my fiancés dog Buster before. He never can sit still in one place. He is always on the move and he's pretty stealth about it. Yesterday I walked in to my closet to grab some shorts. I start putting the shorts on and I hear a tail wagging. I look down and see this! How long has he been there?!?!

He's the best!