Specking as a ex farmer ,it is common to push the testes of a young bull up into the stomach cavity and put a rubber ring around the empty sack.This is a natural method of birth control when running bulls and cows together for beef production.Men can use a similar system using a temporary and wider band enclosing the penis and scrotum preventing the testis returning
I know it works .I used it. and at 55yo now, never fathered any children.