The bokeh? It's a Christmas tree with the lights on in the background. It's just a matter of using a thin depth of field with a dark background and the lights on. In this case I was using a 50mm prime lens set to f/1.8. If you don't have one I highly recommend it as they're very cheap, ultra sharp, and ultra fast for the money.
Get as close as you can to your subject and keep your subject as far away as you can from the background lights and you'll get the smoothing out of the background and the lights flaring up into round discs
The only PP was a bit of noise reduction.