Yes CBT is the commonly used short hand for Cognitive Behavioural Therapy, but it also stands for Cock & Ball Torture.
Cock & Ball Torture as the name suggests, is all about causing pain or discomfort to the male genitals (for sexual pleasure).
CBT includes practices such as: "ball-busting", genital flogging, and urethral play (eg. sounding). Dudes in to CBT might derive pleasure from the masochistic aspect, the eroticised humiliation, or maybe just from pleasing the sadistic dominant who is deriving their own pleasure from stamping on scrotum.
There are many pieces of specially designed equipment for the purpose of CBT play, like ball stretchers, testicle cuffs, or restrictive chastity devices (PICTURED).
Fans of CBT must be careful and take necessary precautions, as some of the practices involved carry pretty significant health risks such as testicular rupture.