Ms Higgins gave detailed evidence on Wednesday about what she says happened in senator Linda Reynolds' office in the early hours of March 23, 2019.
She alleged Lehrmann sexually assaulted her in the Parliament House office after the pair had been out drinking with colleagues.
"I was lodged in between the arm rest and the back of the couch. My head was jammed in the corner," she told the Federal Court.
During Lehrmann's defamation trial against Network Ten and journalist Lisa Wilkinson over a report on The Project on the rape allegation, an emotional Ms Higgins said she had woken up with Lehrmann "lurched over" her.
"He was very much in the throes of it," she told Justice Michael Lee.
"It just felt like he was doing it and it didn't matter, like I was an afterthought."
She said she felt "waterlogged and heavy" during the alleged sexual assault but couldn't call out to security for help.
"I couldnt scream like you see in the horror movies. I don't know. I don't know why I couldn't," she said.
Bruce Lehrmann is suing Lisa Wilkinson and Network Ten for defamation in the Federal Court. (Bianca De Marchi/AAP PHOTOS)
Earlier on Wednesday, Ms Higgins said that Lehrmann had attempted to kiss her earlier after drinks about a week before the alleged rape.
"Mr Lehrmann came up to me. He came into my space and he tried to kiss me on the lips," she said.
Ms Higgins said she felt embarrassed by the now former Liberal staffer's move.
On the Friday night in the hours before the alleged sexual assault, Ms Higgins described Lehrmann as being "handsy" while at '80s-themed nightclub 88mph.
"I was dealing with him touching me. I didn't want it but I was tolerating it," she said.
Lehrmann was criminally charged in August 2021 over the alleged rape in senator Reynolds office in March 2019, which he denies.
His criminal trial in the ACT Supreme Court was derailed by juror misconduct and prosecutors did not seek a second trial, citing concerns for Ms Higgins' mental health.
A landmark report into the ACT legal system and the Higgins case in August made damning findings against former director of public prosecutions Shane Drumgold, which he has sought to challenge.
Lehrmann is also before Queensland courts accused of raping another woman twice in Toowoomba in October 2021.
He has not yet entered a plea, but his lawyers have indicated he denies the charges.
1800 RESPECT (1800 737 732)
National Sexual Abuse and Redress Support Service 1800 211 028
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