A 33-year-old music teacher has been accused of molesting his then 18-year-old student during two private cello lessons with her in 2016.
It so traumatised the alleged victim, the court heard that she cut her wrists with a pair of scissors.
In all, Filipino Carl James De La Cruz Casten faces five molestation charges.
The girl, a polytechnic student, took the stand yesterday, the first day of Casten's trial.
The girl, who cannot be named due to a gag order, said that on July 2, 2016, during a private cello lesson with Casten at a music school where he is an employee, the music teacher had her sit in front of him, between his legs, with her cello in front of her.
Casten, who was seated behind her on the same chair, then allegedly reached out to touch the inner side of her right thigh.
She said he told her she should not lean her chest against her cello, then allegedly slipped his hand into her shirt and touched her chest.
He asked if he could unhook her bra. The girl, shocked, stood up and asked him why. He then dismissed his request and they carried on with the cello lesson.
Feeling "weird", the victim told Casten that she had to use the washroom. She stayed away and only returned in the last five minutes of class to pick up her things.
But Casten allegedly touched her chest over her shirt when she returned. She then left when class concluded.
When she got home, she immediately went to her room and took a long shower, telling Deputy Public Prosecutor Marshall Lim that she had to because "the feeling of touch stays there".
The girl said that when she eventually came out, she hid under her table because she was scared. She also took a pair of scissors and "cut herself" before calling her mother, who was downstairs in the same house, for help.
The girl's mother, who also took the stand today, said when she asked her daughter what had happened, the girl cried and said: "My cello teacher touched me."
She told her mother that Casten also allegedly touched her during the previous lesson on June 25, 2016. Although she initially refused to make a police report, the girl's mother convinced her to do so.
The girl revealed in court that following the incident, she visited doctors at the Institute of Mental Health as she had trouble sleeping, "(felt) the need to be clean" and also felt that she was being followed everywhere she went.
The case has been adjourned for a pre-trial conference, which will be held on July 3. For every charge of molest, Casten faces two years' jail, fine, caning or a combination of such punishments.