SINGAPORE - His first inkling that something might be wrong was when he arrived at the Nanyang Technological University (NTU) hostel at 8pm on Nov 13 last year.
He had responded to an online advertisement posted by an NTU graduate student "to assist in research project regarding body stimulation in forms of light sensation touches".
When he was told to turn up at Graduate Hall 1, he didn't know that it was a student dormitory, the 17-year-old told The Straits Times on Saturday (Jan 20).
But having already spent $16 on the Uber ride from his home in Yishun to NTU, he decided to carry on with the "research project" to cover his costs.
"I needed the money, and it was fast cash," said the teenager, who saw the online ad which was posted on Gumtree on Nov 3. He frequents the site to find part-time jobs.
He was then led to a dormitory room, where he was blindfolded and restrained to a bed while naked. He alleged that the student stimulated his genitals after tickling him for an hour.
The graduate student then paid him $55 to masturbate, claiming he had done the same with another participant, according to NTU's campus newspaper, the Nanyang Chronicle, in an article on Saturday.
He later made a police report. A 25-year-old NTU graduate student was arrested on Saturday for outrage of modesty.
A spokesman for NTU said there is no such research project.
When contacted by ST, the teenager said he felt uncomfortable during the encounter but did not protest or attempt to leave as the student was "a big, very tall guy".
"It's like sitting on a roller-coaster ride - after it has begun, you immediately regret it but it's too late to leave," he said.
He added that he did not tell his parents about the incident and that "they can't know about this".
"Honestly, it's partly my fault for being so naive. It was my first time (participating in a study) and I thought since the student was from NTU, it was legitimate and nothing could go wrong."
He decided to speak out on the advice of a close friend, to warn others against making the same mistake.
He said: "I wouldn't say I'm not angry at him (for what he did), but we all make mistakes at some point of our lives. We both lost something here… I just hope he will learn something from this."