This is a must for those who are just getting into heavier BDSM, and a staple for those that are already past that point. It's probably the easiest CBT device to figure out, aside from a basic cock ring.
The most helpful critical review
A Pleasurably Versatile Experience
This is an inexpensive, comfortable, and versatile ball parachute. It's a classic toy that even someone with nontraditional tastes such as myself can find good uses for as a fun and pleasurable accessory to most sorts of scenes. Don't expect it to be the focus of play, however, because it's just not durable enough for really intense play.