This is something I am just really REALLY into at the moment since I learned to do it on my camera and not just in Photoshop and that gives this technique a whole new experience.
I like to do as much as possible in-camera. It both shows how the end-result will be (almost, usually just a little tweak in contrast and stuff like that) and saves a LOT of time in post processing.
A year ago I had an assignment at school where I used a Holga to make double exposure images with, it was so exciting and I am so happy to have now finally learned to do it in-camera by myself.
I got my boyfriend and our flatmate to pose for me to try it and here are the photos:
I can feel I will be doing more of these and developing them as I go so if you hate them - you'll just have to deal with it.