Former Conservative MP Charlie Elphicke told a woman "we're all at it" as he chased her around his home and sexually assaulted her, a court has heard.
The woman's brother told a trial his sister was "hysterical" and "could hardly get her words out" when she phoned him to tell him what had happened.
Southwark Crown Court heard Mr Elphicke, who was 36 at the time, tried to kiss the alleged victim then groped her breast and chased her around his home while trying to grab her bottom. His wife Natalie was away and his children were upstairs asleep, the jury was told.
The woman’s brother, who cannot be named due to laws protecting the identify of sexual offence complainants, told the trial he spoke with his sister face-to-face two days after her initial phone call.
He told the court: "She said he [Mr Elphicke] was saying, 'I'm a naughty Tory, we're all at it'.
"She said she was sat down having a glass of wine with him at his request. He made advances towards her and made a lunge at her.
"She was upset. She found it hard to give a systematic account. She said she was 'attacked', she was 'assaulted', words like that.
"She indicated it was a sexual assault, he tried to grope her in sexual places and tried to kiss her. She told me she pushed him away."
Defence counsel Ian Winter QC said the brother's police statement, taken a decade later, made no mention of the phrase "we're all at it", and suggested it was a detail added to his account following conversations with his sister.
"The reality is you have talked about this with your sister and that's why you've got more details and information for us today than you had before,” Mr Winter said.
The brother replied: "No, that's not the case at all."
The witness said his sister was “very upset on the phone” in the call in which she told him what had happened.
He added: “She was hysterical, in a bit of a state, she could hardly get her words out properly.
"She didn't go into much detail ... she said she had been attacked."
Earlier, the woman's sister described receiving a similar call moments after the alleged attack.
She told the court: "[My sister] phoned, she was quite distressed, she was talking quickly. I had to ask her to calm down.
"She was clearly distressed, she was saying, 'He chased me round the kitchen'.
"It was a highly emotionally charged situation.
"When I recalled it to my husband [later], it just seemed totally bizarre. It seemed like something out of sketch show Benny Hill."
Mr Elphicke is also accused of sexually assaulting a second woman who worked in parliament in 2016. He denies three counts of sexual assault.
The Conservative was MP for Dover from 2010 until 2019, when he stood down and was succeeded by his wife.
The trial continues.