We don't know either???

I came home today and as usual was met by an excited little boy, one of the highlights of my day for sure. I got loves and kisses and we settled in. I came out to my computer to check my email and after a few seconds he'd had enough sitting at the computer and wanted to play. I put him down and this is what he started doing....

You can't really hear it in the first segment it's right the beginning but if you listen towards the end of the second you'll hear him. He did it several times before I could get the camera out but this is all we captured. We don't know what he was doing either, we think he was trying to give the floor a zerbert.