A list of cameras that I've done double exposures with, and how to do it.
Nikon F2
Take the first shot, then push in the rewind button on the bottom of the camera. Wind the camera to cock the shutter, which will not move the film. Push the rewind button for each additional exposure if needed.
Nikon FE
Move the small lever next to the shutter button up for each successive shot. It resets each time.
