What do you see when you close your eyes.

Here's something trippy to try that doesn't involve closing your eyes. Get your computer showing something generally white and then wave your hand or hands quickly back and forth, and you'll observe to your amazement the trails your fingers make: creating the illusion of more than 5 fingers.

Good way to stimulate closed eye hallucinations is to press your eyes into your arm or something, apply a little force to a part of your eye. I usually see floating masses of triangles and discordant dots of colors, sometimes it'll stay at one color and change to another periodically.

On the topic of kinda weird things to do with yourself. My friend told me that if you take the eraser side of a pencil... and rub a part of your eyeball over your eyelid, you can find a kind of euphoric spot. It's a strange sensation. Ah, I found it. Yeah, use the eraser side of a pencil, like a point of the eraser and try rubbing around the upper left of your right eye (your actual eyeball, with the eyelid over it) or upper right of your left eye (presumably.) You don't need to rub hard, just a slight circular motion.

Jam it back in, in the dark.