Parktown Boys High School's former water polo assistant coach is alleged to have raped schoolboys by putting his fingers inside their anuses on "numerous occasions".
These graphic details emerged during the trial of Collan Rex at the South Gauteng High Court which is sitting at the Palm Ridge Magistrate's Court in Ekurhuleni.
On Thursday morning, prosecutor advocate Arveena Persad called two teenage witnesses to testify against Rex, who is accused of rape through an alleged sordid act of preying on children and putting his fingers through the learners' buttocks.
Rex, the 22-year-old former Parktown water polo assistant coach and hostel master, has already pleaded guilty to 144 counts of sexual assault he admitted to doing in a two-year reign of terror from 2015 to 2016.
One of the teenagers, who was testifying in the told the court that during the study session break at the school hostel, Rex allegedly put his arms around the him to try and penetrate him anally. The boy was 15-year-old at the time.
The boy, who is still at Parktown Boys and was in Grade 9 at the time of the alleged rape, said he fought Rex off to protect himself. The State is again using an intermediary to assist the witnesses who are minors and to prevent "undue mental stress" during their testimony.
Rex, although pleading guilty to 144 counts of sexual assault, has pleaded not guilty to 183 additional charges ranging from attempted murder, rape, sexual grooming and exposing minors to pornography.
The trial continues.