A 12-year-old boy is on trial at Bradford Crown Court accused of raping two boys, aged five and eight.
The slightly-built youngster is also accused of sexually assaulting the boys.
The accused boy is thought to be one of the youngest children to be tried for rape in West Yorkshire.
He denies all the offences.
The boy is alleged to have assaulted the boys in a garden in the Bingley area on August 22 last year.
The boys told the court they had to perform sex acts to be allowed to bounce on a trampoline.
The trial judge, Robert Bartfield, is sitting without his formal wig and gown so the 12-year-old defendant does not feel intimidated.
Prosecution and defence counsel are also in plain suits.
The judge told the jury yesterday that it was "a very sensitive and unusual case".
Before they were sworn, potential jurors filed to the front of the court to look at the boy and his parents to see if they knew them.
The boy, wearing a zipped top and a scarf, was seated next to his father, behind his barrister Rebecca Young. His mother was in the public gallery.
Prosecuting counsel John Lodge told the jury of seven women and five men: "This case is about three children."
He told the panel rape could be a "dreadful and unspeakable crime" but it covered a wide variety of different acts.
He said the boy was accused of rape and sexual touching.
Mr Lodge said there might have been an element of childish experimentation by the 12-year-old. After the sex acts, the boy told his young victims not to tell anyone, the jury heard.
But the five-year-old went straight to his grandmother and the police were called.
Mr Lodge said the 12-year-old admitted he asked the younger child to perform a sex act but he insisted to police that nothing had actually happened with either boy.
The eight-year-old boy told the jury via video link that the 12-year-old threatened to slap him if he did not do what he asked.
"It was gross, horrible and weird," he said.
The boy said he had first denied anything sexual had happened because he was scared his pocket money would be stopped or he would not be believed.
He said that when he was abused he felt sad to be doing "something so ridiculous".
The trial continues.
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