"My body went rigid and I couldn't fathom what was happening."
Later she said: "I didn't say anything and I didn't know how to tell him to stop."
She said she asked Marinovich what he was doing, and he stopped only when his father came into the gym.
"Nik pulled my hoodie down over my head so his father couldn't see me."
She said Marinovich told her that his father was stoned and wouldn't remember anything. He then suggested they go upstairs.
"I was really shocked. I felt like I was just in survival mode. I felt [going] upstairs was going to give me the opportunity to put some distance between us."
The woman said Marinovich took her by the hand and led her upstairs. Once there she asked Marinovich to drop her home.
Crown prosecutor Tiffany Robertson asked if there was a conversation in the car on the way home.
"All I can remember is he said to me not to tell anyone. He also made the comment that I was only 'kind of pretty'. It was really weird ... that I was only 'kind of pretty' compared to the other cheerleaders."
Initially she didn't tell anyone what had happened.
"I was just so embarrassed. I just couldn't believe it had happened and I was so embarrassed because the club was so ... not like a cult ... but it was so connected. He had all these people around him who appeared to like him."
She said she later told her brother and another cheerleading coach, but a lawyer told her not to pursue her complaint and she left the club soon after.
Under cross-examination from Marinovich's lawyer Richard Earwaker, the woman confirmed that she had needed to work on specific skills to advance in the sport.
She denied that Marinovich's father came in and out during the session, and that she was making the whole thing up.
Mr Earwaker also asked if she was "ambitious" in the sport. The woman said she wanted to do well "but it wasn't the be-all and end-all".
Under questioning from Judge Russell Collins, the woman said Marinovich sent her up to 40 text messages inside a month-and-a-half.
The case was set down for up to six days but Judge Collins has told the jurors that it could finish on Thursday.