He is the fifth and final complainant to testify in Jones's marathon trial against indecent assault and sexual touching allegations dating back to 2003.
The man was aged 13 when he opened up about his family's personal and financial difficulties to the then No. 1 radio identity in Sydney, who agreed to help.
Jones advocated on the family's behalf, liaised with his political contacts, and spent more than $100,000 assisting with their issues over several years.
The then-teenager and Jones shared hundreds of emails during that period, including discussing the cost of resolving some of the family's issues.
Under cross-examination on Thursday, the complainant agreed his mother had input into some of the emails but insisted he had written them.
He hotly denied he had been intent on obtaining as much financial assistance as possible from the veteran broadcaster.
When it was suggested his mother had that intention, the complainant retorted: "That is a lie".
He also denied Jones's barrister Gabrielle Bashir SC's suggestion he had tried to deceive the broadcaster by signing off certain emails with only his name when his mother had made contributions.
When the boy was 16, Jones emailed him to say the costs were "out of hand" and declare "enough is enough".
"There must come a point where I have to say no more," the now-retired political commentator wrote.
The complainant told the court he didn't read the email as an indication that Jones's financial assistance was ending but instead as a sign of the broadcaster's frustration.
He replied with an offer - on behalf of himself and his mother - to arrange to repay the former Wallabies coach, but it wasn't accepted.
The discussion came months before Jones invited the complainant, then 17, to stay at his home in the NSW Southern Highlands during the school holidays.
He was not accompanied by a parent and there was no one else in the house when he leaned in to give the former ruler of Sydney's airwaves a goodnight hug, the now-adult has testified.
Jones kissed the teen and stuck his tongue in his mouth, causing the 17-year-old to freeze, he told the court.
He recoiled and stepped away when the then-septuagenarian grabbed his bottom without consent.
"I said 'that's enough, Alan'," the then-teenager told the court emotionally.
As he turned to enter his bedroom, the complainant said he saw the radio host had a grin on his face, which made him very uncomfortable.
"I went in (to the bathroom) with a loofah sponge and I just soaped it and scrubbed my mouth as much as I could," he recalled.
"I felt violated and I felt gross."
The complainant told the court he was terrified of jeopardising the support his family had been given by making a scene.
Days later, he told his mother something of a sexual nature had happened to him at Jones's property but gave her a note because he didn't want to discuss it.
Jones has been charged with one count of indecent assault in relation to the teenager, which he has denied.
The 85-year-old has pleaded not guilty to 21 charges of indecent assault and sexual touching against five men, maintaining the allegations have been concocted.
The marathon hearing, which began in August, is set to conclude in November.
1800 RESPECT (1800 737 732)
National Sexual Abuse and Redress Support Service 1800 211 028
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