The man, aged 46, told the High Court in Glasgow that 71-year-old James Torbett – who he knew as Jim – would on occasion stuff hundreds of pound notes into his mouth while abusing him.
He said: “Sometimes he would give you money. He would fit it into your mouth using his hand.
“One time it was £530. I remember going home with £100 notes in my pocket.”
The man, who lives in the Glasgow area, also claimed that on a trip to Noyon in France with Celtic Boys Club Torbett did a” striptease” to music before abusing him.
The witness, who cannot be named for legal reasons, told prosecutor Sheena Fraser: “I was in my bed in a dormitory. Jim Torbett was standing there with a shirt and underpants on.
“He proceeded to do a striptease. He took his shirt off and was dancing.”
The man told the jury that Torbett, who still had his underpants on, was moving the shirt back and forwards between his legs. He claimed that Torbett then summoned him to his room and abused him.
At times during his evidence the witness appeared upset.
Torbett, 71, from Glasgow, denies sexually abusing four young boys between August 1985 and August 1994 at various addresses in Glasgow, in his Mercedes, and in London and Noyon in France.
The witness said that he also phoned Police Scotland and added: “They never came for a couple of days and I went into a huff and I told them lies.”
He told the court this was because his mother was there when the police arrived.
The trial before judge Lord Beckett continues.