Kinktionary
More like guidelines and a lot less like definitions.
Cock & Ball Torture (CBT)
Cock and Ball Torture centers around inflicting pain and punishment on the male genitalia, including the penis, scrotum, and/or testicles. Depending on context, this might be given by Top role such as a Castrator / Castratrix, or by a Sadist.
Cock and Ball Torture is commonly abbreviated as CBT, which shouldn't be mistaken for cognitive behavioral therapy which is also often abbreviated as the same letters. While Cock And Ball Torture can change male behavior in a play setting it is not considered a standard therapeutic technique! However, it could be said that there is still some psychology involved in Cock And Ball Torture as it runs to the core of the male psyche to have pain inflicted upon such a anatomically sensitive and vulnerable place like the cock and balls.
Receiving CBT is generally viewed as a masochistic activity which often is submissive. Those inflicting the CBT may or may not be sadistic, but typically the giver is exerting dominance over the male receiver. Light to moderate CBT is not particularly sadistic; however, CBT is a dominant/submissive act between the giver/receiver.
Cock and Ball Torture can sometimes be related to the practice of chastity too (particularly with spiked cock cages).
In general the most sensitive male anatomy include the testes and the glans (head) of the penis. The shaft of the penis is relatively insensitive yet does have superficial blood vessels that can be ruptured resulting in mild bruising, which is relatively harmless and will fade in less than one week.
Safety & Consent
Dangerous activities within CBT consist of prolonged restriction of blood flow or compressing the testes against a hard surface or the pelvic bone. When done with sufficient force this can rupture the tunica albuginea, which is the outer fibrous covering of the testes. A force of >80 pounds per square inch (PSI) against a hard surface can rupture a testicle, causing permanent damage.
See also: Clit and pussy torture