Abacus Vice Double Bar Pincher

Every slide of the rubber O-rings increases the cruelty!

Place your nipple between the steel bars, then slide the rubber bands toward it. The closer they get, the tighter the pinch. There are six O-rings, so you can arrange them for a tighter pinch, or clamp down on multiple points. Of course you don't need to limit it to nipples. It can stretch far enough to fit around a thumb tip.