do a fake ouji board routine. we did that with friend years ago when we were teens who "didn't believe in all that ****!". we talked to his mom( who thought the idea was funny ) got a couple of "family secrets" so to speak and then we brought out the board. he was laughing at us a first but by the time the board went to him and started spilling stuff he looked like he was going to faint! then we all "decided' to head for home right after and of course no one was walking his way. i thought that was going to make him cry.
it takes a little practice in advance, but you can get to the point where you can move the board and look like you are just resting your fingers on it.