Clothes peg
From wipipedia.org

Clothes pegs can be applied to almost any part of the body; their cheapness means that they can be applied in large numbers on the victim. When first applied, the clothes peg is not usually that painful, but as time passes the level of pain increases. Like nipple clamps they are often most painful as they are removed. A zipper is a number of clothes pegs linked by a string or cord attached to a victim. When ready the cord is pulled and the pegs are pulled from the body in rapid succession causing an intense experience for the sub.