Blanket with buttons on the sides?

So for Christmas i got this fleece blanket that has several buttons on each side. I didn't keep the packaging and just stowed it away in a closet because i already have a Snuggie, and the thing was obviously some knockoff. Now I'm kind of curious as to how this thing works but I don't have any instructions or even know what the thing is called. i was hoping someone could help me. Its just a blue fleece blanket with buttons on each side. any help would be appreciated