Cell popping is a form of body modification where a red hot needle or poker is used on the skin to create a tiny round burn; a series of such burns can be made into a pattern, much like a tattoo. While it involves pain like cutting and needle play, it is also a form of branding. When done correctly, the brand is long-lasting but not permanent.
The practice is also referred to as micro-branding or devil's fire.
More About Cell Popping
Cell popping can be used as a form of pain play because the hot needle causes pain and an endorphin rush, which can send a submissive to subspace. It might also be used in Dom/sub relationships (with consent) where the dominant uses the method to brand their submissive. The practice is referred to as a method of temporary body modification. The needle that is used is small and the shallow depth that it is inserted mean that the body can heal these wounds relatively easily.