No, I’m gonna tell you how it works, Mr. Mayor.

A crooked Mayor de Blasio crony testified in court Friday just how easy it was to keep Hizzoner under his thumb, describing how he just had to dangle some money and City Hall jumped to do his bidding.

Mayoral donor-gone-rogue Jona Rechnitz — during his second day of explosive testimony in Manhattan federal court — said de Blasio campaign staffer Ross Offinger hit him up for a $102,000 donation to help keep state Senate Democrats in office after de Blasio won the 2013 mayoral race.

The shady real-estate developer said he initially balked at the request, sniffing that he wasn’t getting the favors he wanted from City Hall. Plus, Rechnitz said, he deserved more personal attention from his pal the mayor.

“I told [Offinger], ‘No, I’m out on this,’ ” testified Rechnitz, who was a cooperating witness in since-closed state and federal probes into de Blasio’s fund-raising. “I was frustrated that we had a lot of requests and issues on the table that weren’t being attended to in a timely fashion.

“All you do is you come here when you need money,” he said he griped to Offinger.

In particular, Rechnitz said, he wanted help with a slew of violations he had received because a tenant at his Madison Avenue property illegally sublet his apartment on Airbnb.

“I paid all the violations,” Rechnitz said of his tenant’s illegal sublet. But he said he wanted to meet with someone in the Housing Department to explain why the violations were unfair, and had been asking Offinger “for a long time” to arrange a sit-down.

Rechnitz said he also asked for more information from the city on an Ocean Parkway home his friend was considering selling — and his request “wasn’t moving quickly enough for my liking.”

“I was sick and tired of it,” Rechnitz said. “I wasn’t getting the proper forum or attention that I wanted.”

The disgraced donor said that after he refused to cough up the dough, things got moving. He soon got a personal phone call from de Blasio, Rechnitz said.

“The mayor told me it means a great deal to him,” he said of the donation. Rechnitz said that prompted him to make the hefty contribution. “Once the mayor called me, I felt it was a personal favor to him,” Rechnitz said.

Then came the donor’s payoff, he said. Rechnitz said Offinger got him “a meeting with the city” to discuss his Airbnb violations and he got “answers on the Ocean Parkway property.”

The donor testified Friday at the bribery trial of former city correction-union boss Norman Seabrook. Rechnitz allegedly bribed Seabrook to convince him to invest $20 million in union pension funds in a pal’s flailing hedge fund.

Rechnitz said he once helped out the mayor by convincing Seabrook to be “nicer and kinder” to Joseph Ponte, de Blasio’s beleagured pick to head of the city Department of Correction.

An e-mail introduced into evidence Friday — sent to de Blasio from Rechnitz in May 2014 — reads, “Norman under control.’’

When asked about the message, Rechnitz said it was referring to his offer to help de Blasio rein in the outspoken head of the correction-officers union, who felt Ponte was the wrong man for the job. “Norman had been very outspoken about the new commissioner,” Rechnitz said. “Since Bill and I knew each other, we spoke often, and he was frustrated. I told Bill, as a favor to him, I would speak to Norman and get him to meet with Bill and be nicer to him.”

Seabrook eventually told Rechnitz he would not be as “outspoken in the papers” about Ponte, who was ultimately driven out of office amid a scandal over his misuse of a department-issued vehicle.

As the Seabrook trial continued Friday, reporters mobbed de Blasio in Brooklyn during his first public appearance since Thursday’s bombshell pay-to-play testimony — but the mayor just kept grinning as he walked to his car.

Mayoral spokesman Eric Phillips denied Rechnitz’s stunning accusations.

“If Jona Rechnitz says he bought the mayor, he is a liar,” Phillips said. “If he says he had unfettered access, he is a liar. The only thing Jona Rechnitz can say honestly is that he is a failed fixer of grand delusion just trying to save his own skin.”

Additional reporting by Lia ­Eustachewich