A female Rikers jail captain once suggestively twerked for a male prisoner as part of a creepy deal to get him to cough up a contraband razor, says a lawsuit charging a culture of cover-ups at the infamous lockup.

Former guard Manuel Carvalho Calvelos claims in his Manhattan federal lawsuit filed this month that he was fired for blowing the whistle on such seamy behavior — as well as rampant corruption.

“Manuel had a legal obligation to report the illegal activities and corruption he witnessed within the Department of Correction, and he took that duty seriously,” his lawyer, Phillips Hines, told The Post.

“Unfortunately, those at DOC that decided to terminate him do not.”

The plaintiff’s supervisors were intent on improving the embattled jail’s statistics, including involving assaults, as they silenced him, Calvelos’ suit says.

In the twerking incident in May 2017, a DOC captain danced for a masturbating inmate to get a razor in the prisoner’s possession, the suit alleges.

When Calvelos reported the incident to three supervisors, “The captains … smiled and dismissed Plaintiff without taking further action,” according to the suit.

The former corrections officer later reported three other guards for smuggling in contraband and planting it on inmates after assaults on employees — but the same trio of supervisors didn’t follow up on the allegations, according to the suit.

Days after reporting the illegal activity, Calvelos said he was written up for violating the uniform policy but that it was only in retaliation.

The suit also claims that when he was punched in the face by an inmate, nearly breaking his nose, in March 2017, Warden Clement Glenn and one of the three supervisors told him to “hold it down” and report it only as a use of force, not an assault.

Such allegations echo a city Department of Investigation report from April that found there was no way to track assaults on staff at the jail.

Calvelos worked at the Department of Corrections for nearly two years before being let go Jan. 5, 2018 — eight days before his position would be permanent — with the agency citing two use of force incidents.

He and his lawyer say his firing was in retaliation for his whistle-blowing.

A DOC spokesman told The Post that Calvelos’ “allegations do not in any way represent the hardworking New York City correction officers who come to work every day as part of a law-enforcement community dedicated to helping keep New Yorkers safe.”