In the Dungeon demo I picked up two nipple clips and weights and double clipped. I can no longer see them. What do I do to see them, use them, drop them?

If you drop them, they hit the floor, and can be difficult to see.

To use them, pick them up, and approach the model. Hold the clip near where you want to attach (nipple or clitoris), and it will take on a new appearance. Then click to attach. It can be a little jittery at times, so be patient. Weights are attached in a similar manner, by holding them near the end of the chain.