Penis cage: Any of a number of plastic or metal devices designed to limit access.
Full belt: Limits access to genitals and has a locking belt as well.
Short periods: From a few minutes to a few weeks.
Extended periods: Usually for several months with occasional removal for cleaning or teasing.
Clips & Clamps – Often used to inflict pain for punishment or during teasing.
Nipples: Clothespins (pegs), various types of clips and clamps made for such use.
Scrotum or penis: Usually done as a part of CBT (cock & ball torture) Bottom: Clothespins work well here. They are not as painful as as nipples.
Other: Can be used on any part of the body where enough skin can be pinched.
CBT - Cock & Ball Torture Rope or string: Often used to bind the penis or balls in uncomfortable positions.
Candle wax: Dripping of candle wax onto the body (use caution not to burn).