The woman has accused Ryan John Zabaznow, 37, of sexually assaulting her after she passed out inside her donga in Newman on November 18, 2020.
He denies it and told the District Court in Perth on Monday the sex was consensual and he has the Facebook messages to prove it.
But the woman, who cannot be named for legal reasons, disagrees.
"I remember waking up to Ryan over the top of me," she said from the witness box on the first day of Zabaznow's trial for sexual penetration without consent.
"He was penetrating me ... I wasn't really sure what was happening."
The woman said she had been stripped naked from the waist down and Zabaznow's body felt like a "cement slab" on top of her.
"I remember him saying how sexy I was," she said, wiping away tears.
"He had one hand at the side of my head and the other on my hip ... thrusting his body."
She said she was crying during the incident and didn't know whether to scream or yell.
"I thought don't let him see you're upset so I just cried as quietly as I could," she said.
The court heard the pair had been at the camp's bar or wet mess earlier in the night and continued socialising in the dongas of colleagues after it closed.
Zabaznow joined the woman and other co-workers in a colleague's room after messaging her via Facebook.
The pair shared an intimate conversation about their past relationships before leaving for the woman's room with a few other co-workers for more drinks after security guards moved them on for being too noisy.
As the night wore on the woman, who said she drank about 15 mid-strength beers, started to feel unwell.
A friend helped put her to bed after she vomited while Zabaznow and another man sat outside and continued drinking.
After the woman's friend left, Zabaznow allegedly entered the drunk woman's room where she was passed out and climbed into her bed.
The alleged rape stopped when two other workers heard "sex noises and moaning" and knocked on the woman's door to check if she was OK.
They found Zabaznow in bed with the alleged victim. One of her colleagues asked if it was consensual.
"(She) asked if I was OK and I couldn't respond. I just cried," the woman said.
"(The woman who had knocked on the door) was quite upset. She told me to get him out of my room."
Zabaznow was allegedly defensive as he left the donga, according to the woman.
"I'm not some c*** like she's making me out to be," he is alleged to have said.
The woman repeatedly told the court the sex was not consensual. Her friend confronted Zabaznow about his alleged actions after the incident.
But Zabaznow's lawyer, Helen Prince, said social media messages sent the morning after the alleged rape told a different story.
"What the f*** you just made a f***ing scene," Zabaznow wrote in one.
"It's all good (my friend was) just concerned because of the state I was in when she put to me bed," the woman allegedly wrote in reply.
"You're not a c***. It's all good.
"They were just worried about me because I'm going through a lot."
The court also heard the woman and Zabaznow exchanged a series of messages before the alleged incident, including smiley emojis with love hearts for eyes as they arranged to meet.
The woman allegedly told a supervisor the sex wasn't non-consensual.
But she told Ms Prince during cross-examination she was "trying to defuse the situation".
The trial continues on Tuesday.
1800 RESPECT (1800 737 732)
National Sexual Abuse and Redress Support Service 1800 211 028
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