The friend testified about the conversation as Jones fights 22 charges of indecent assault and sexual touching without consent in relation to six men.
Eight charges relate to the former radio staffer, who claims he was kissed without consent in lifts and groped by the former top-rating breakfast radio host while driving and at an event.
His friend recalled being shocked when the staffer told him Jones had squeezed his crotch while he was driving.
"I said 'what the f***?' and he said to me 'that's just Alan, that's his behaviour'," the friend told Sydney's Downing Centre Local Court.
The pair didn't speak about the allegation any further and haven't talked about it since.
The staffer told his friend Jones was a "very powerful person", the court was told.
He used the words "go the grope" when describing how Jones would put a hand on his leg, a former colleague testified.
She said the staffer recounted brushing the longtime shock jock's hand off his leg and saying no, which led Jones to laugh it off.
The complaint had been made in a jovial sort of way, the former colleague said and they didn't discuss it again.
Jones, 85, has pleaded not guilty to the charges related to six men, alleged to have occurred between 2003 and 2020 - the year he retired.
Two other friends told the court the radio staffer made the complaints in a joking manner in group settings before his anonymised allegations were published by the Sydney Morning Herald in 2023.
"I remember him saying 'I can call Alan anytime of the day and he'll answer my call'," one said, characterising the comment as "odd".
The radio staffer wrote a group message to his closest friends on the eve of the article's publication to forewarn them, the court was told.
"Lads there will be a big story about Alan Jones and a lot of f***ed up things he did to me and others," he wrote.
His father-in-law said he was "surprised" to learn the man was considering taking action against Jones, including considering civil alternatives.
"(The radio staffer) told me he was absolutely sure he was doing the right thing," his father-in-law wrote in a statement to the court.
He said the staffer had told him Jones pushed him up against a wall and kissed him.
His son-in-law also described the breakfast host inviting him to his apartment, where he was sitting in only a dressing robe so "his undercarriage was hanging out".
The radio staffer previously rejected suggestions he had fabricated the allegations or come forward to benefit Jones's rival and 2GB stablemate Ray Hadley.
Jones, whose 35-year career spanned TV and radio, has dismissed the allegations by the six complainants as false and motivated by matters including rivalry, treachery and hatred.
The trial, expected to run four months, continues.
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National Sexual Abuse and Redress Support Service 1800 211 028
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