I can't figure out how to get a picture in here, but the "Tower of Pain" separates the real nipple sluts like me from the posers!!!! I LOVE it.
A several inch base goes vertically on your chest, a threaded rod goes up from it perpendicular to your chest, and through a lucite rod. Dangling from the ends of the rod are 2 clover clamps (they are the ones which only grip your nipples tighter as the are pulled on or tension is applied). On the end of the rod is a large ball you twist which pulls the lucite rod further and further from your chest. Do it gradually and it's amazing how much stretch you can get on your nipples.