Nipple clamps

Nipple clamps are sex toys that usually come in a pair, often connected to the other with a chain. You can even buy weights for the nipple clamps to increase the pressure by creating more pinching and pain

CNC scenes,

Many couples use a clothing item or piece of jewelry to indicate they are open to unplanned CNC scenes if their partner wants to initiate it. For instance, if a particular scarf is worn or there is a bracelet on the kitchen counter, it has been pre-negotiated that free use is then in play.