In most terrestrial mammals, the scrotum or scrotal sac is a part of the external male genitalia located at the base of the penis. It consists of a sac of skin containing the external spermatic fascia
A human's scrotum in a relaxed state (left) and a tense state (right)
Image showing musculature and inner workings of the scrotum
Cock and ball torture is a sexual activity involving the consensual application of pain, pressure, or constriction to the male genitals. Practices can include squeezing, genital spanking, genital pier
Scrotum
…surgery that creates a scrotum for trans men using tissue from the labia majora, or a plastic surgery that repairs or reconstructs the scrotum. Cock and ball torture is a kink that may involve bringing pain to the scrotum. Beyond kink, a person (especially a man) may hit someone in the testicles as a gendered cultural…
Ballbusting at the Folsom Street Fair in 2018.
A metal ball stretcher and cock ring, which forces penis' erection
Kneeling man wearing a humbler
Urethral fingering is an example of CBT needing special precautions, such as not having a sharp nail on the finger inserted inside the penis. Image shows a woman doing urethral fingering.