The British actor and comedian, 51, is accused of sexually assaulting the woman in the mid-2000s after encountering her at the Choice FM studios in central London.
She told Southwark Crown Court on Tuesday that Brand appeared to find it funny after grabbing her breasts and forcefully kissing her.
She told jurors that three men and a woman with Brand witnessed the incident and "did nothing", other than to laugh afterwards to "break the silence".
When faced with questions about her account, the woman said: "This was a situation I did not want to be in.
"I wanted it to go away. I don't gain a single thing by saying 'Russell Brand did that to me'.
"I have nothing to gain at all."
Describing the alleged assault, she said Brand was a "perfect stranger" to her and she recalled him saying "aye, aye" before grabbing her face.
"He was kissing me and he was pushing his body against me," he said.
"It was hard, I would say it was sloppy.
"He was kissing me all down my neck. His hands at that time were all over me.
"He touched my bum, touched my breasts, hands on my waist, his other hands were pinning me so his body was pressed up against me."
She added: "It was rough, it was very, very rough. It was hard, I would say that his whole body was pressed against me, the kisses were hard and sloppy, going down my neck.
"The reason I used the word frenzied is because it was just ... violent.
"It was hard and he just wasn't stopping."
She told the court she was "stunned" and "in a haze", she said she pushed Brand away and told him to "f*** off", and added: "He kind of stumbled back, then it was just still."
She said: "I remember he made like a sound, that was like funny - ha ha - like that."
She recalled a man who "started laughing, almost like it was to break the tension".
She told the court she looked to a woman who witnessed the assault, but she "didn't say anything".
She said the three men also did nothing to intervene.
Brand denies three counts of rape, three charges of sexual assault and one allegation of indecent assault.
Jurors have heard he says sexual encounters were consensual and some of his interactions with women have been "reimagined" in recent years.
Among the allegations, he is accused of raping a woman in a hotel room in 1999 and forcing an MTV worker into a sex act in a Soho bar.
The trial continues.
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National Sexual Abuse and Redress Support Service 1800 211 028
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