Swoop, I immediately had to try it and it works! You have to play around with the settings, but its really worth it. I use M with Autofocus and low f number, the lights should be as far as possible in the background.
And the best is, you can make a bokeh set in seconds!
I used a circle punch (5cm, 2") which fits my 52mm lens pretty good.
Get creative and cut out the shape you want. Here´s what I did...
The diameter of my shape is 1cm, that works fine with my lens. You might have to adjust the height and width of your shape according to the lens you use. There is some physics behind it, but I don´t dare to try to explain it here :-)