Turn out all the lights and have your model hold a detachable flash in her hands!
For these pictures I turned all the lights off and had my model hold a detachable Coloursplash flash in her hands. I set my Holga on bulb setting and held down the trigger. Every time she pressed the flash button she would move into another position.
My model would mix it up and choose different colour filters to put on the flash to create crazy colours.
They didn’t turn out quite as I expected. Most were overexposed but still pretty cool.