Speaking to police last year, he said he looked up to the defendant and often joined him at parties in hopes of growing his own profile. At the events, the defendant would ply him with alcohol despite his age at the time, he told police.
"I was very, very, very drunk," Mr A told police, explaining that he left his drink at one point with the defendant so he could visit the toilet. "I remember having a couple more drinks but feeling quite fuzzy. It would have been brought on by drugs, and I had not voluntarily taken any."
The next thing he remembered, he said, was waking up naked in the defendant's bed with the defendant performing a sex act on him. Seeing the teen was awake, the defendant stopped, put on clothes, smiled and left the room without saying a word, the accuser said.
"I was almost in denial that it happened," he said, explaining that he grabbed his belongings and left immediately. "I kind of played it in my mind like it was nothing, but in truth I knew exactly what happened and I was really scared."
The two didn't talk for several weeks but remained friends, he told police, explaining that he would often try to keep his distance by telling the defendant: "Mum says I have to go home now".
About a year later, after a night of alcohol and MDMA, he again blacked out and woke up in a similar situation in the defendant's bed, he told police.
"I freaked out," he said, explaining he asked the defendant: "What the f*** are you doing?"
"He was trying to tell me it was okay and I wanted to do it. I know in every fibre of me I would never do that."
Police asked how he felt about the two incidents he described.
"Angry — really, really, really angry," he said. "[He was] taking advantage of me and putting me in a position where I couldn't do anything. I wasn't even awake. That's disgusting. It makes me want to throw up."
Throughout the years they knew each other, Mr A estimated that the defendant also blackmailed him into a sex act roughly half a dozen times. On the witness stand, he described several of the alleged instances to jurors.
"I would always say no. The alternative would be threatening to destroy me in terms of leaking [nude] photos he had of me or using his social media presence," the accuser said. "I would then do whatever he wanted."
The defendant started his trial this week by pleading guilty to possession of MDMA, found in his home when police searched it, and to having punched the accuser at a party. But he is innocent of all other charges, defence lawyer Emma Priest said during a brief opening statement.
The accuser is expected to face cross-examination tomorrow as the trial continues. The second accuser, known as Mr B, is also expected to testify this week.