Cops in Mountainside, New Jersey have allegedly given a whole new meaning to “long arm of the law.”

The entire police department was called out last week in a lawsuit, along with borough officials, for allowing “harassing, inappropriate and illegal conduct” — including the unabashed use of a large dildo dubbed “Big Blue” to pick on fellow officers.

Five Mountainside cops and one employee are suing the borough, claiming they let the abuse go on for years.

Their accusations are aimed at two officers, one of whom was named “Cop of the Year” by the local Police Benevolent Association in 2014.

They include getting hit in the head with Big Blue, forced tickling, ramming a flashlight “up the backside” of male officers, flashing their testicles at other cops — and even placing them in people’s food.

The allegations were outlined in court papers, which were obtained by The Post.

Mountainside officials released a statement Wednesday in response to the suit, which identified the involved parties.

Officers Christopher Feighner, Richard Latargia, Thomas Norton, Jeffrey Stinner, and James Urban are the ones suing the borough, along with part-time department employee Amy Colineri.

In their complaint, the group claims that they experienced a “hostile work environment” due to the actions of of their fellow officers, identified as Thomas Murphy and Andrew Huber.

The pair was known to wield Big Blue regularly, sometimes even going so far as to bring it to department dances — despite there being a strict rule about not having sex toys in the workplace, the complaint says.

Huber, now an Internal Affairs officer, is allegedly the one who gave the dildo it’s nickname.

At first, he kept Big Blue in his desk drawer — but he was later forced to move it to a filing cabinet after it sparked outrage, the complaint says.

Huber started allegedly using the large blue dildo to harass his fellow officers “in or about 2007 and 2008.”

“While Plaintiff Stinner was assigned to the Detective Bureau, Stinner would be subjected to Big Blue on an almost daily basis,” the complaint says. “Huber would waive around Big Blue, throw it within the Detective Bureau, and throw it at people walking past the Detective Bureau.”

On one occasion, “Plaintiff Urban saw Big Blue in a coffee mug.”

Upset, “Urban removed the dildo from the mug and threw it in the garbage,” the complaint says.

But Big Blue turned back up, and continued to wreak havoc on the Mountainside Police Department — despite years of protest, the complaint says.

Department brass tried bringing in an attorney to discuss the dildo debauchery, but the cops allegedly didn’t listen.

“Huber stood up and left the room,” the complaint says.

In 2015, Huber allegedly attacked a male dispatcher with Big Blue at police headquarters while Murphy filmed the incident.

“Huber stuck Big Blue in the male dispatcher’s face and hit him over the head with it,” the complaint says. “Murphy laughed and stated, ‘Get him,’ ‘What’s it smell like,’ and ‘I hope it doesn’t smell like what I think it smells like.'”

When Huber and Murphy weren’t using Big Blue, they’d allegedly go after cops with flashlights.

“Murphy had a practice of taking his flashlight and ramming it into the anus area of other male officers,” the complaint says.

As a result, cops would allegedly attempt to walk with their backs against the wall.

“On one occasion, Murphy hit Plaintiff Urban with the flashlight so hard that it hurt for Urban to sit down,” the complaint says.

Another portion of the alleged abuse came in the form of a sick and twisted game, known as “braining.”

“This is a reference to Huber taking his testicles out of his pants and placing his testicles on someone’s food, drink or person,” the complaint says. “Either Huber or Murphy would take a picture of [the other] ‘braining’ an item without the target officer’s knowledge.”

Plaintiff Norton claims to have witnessed the alleged “braining” on multiple occasions — starting way back in 1998.

A slew of other allegations were listed in the complaint, including claims that Huber “would hide quietly in the bathroom stall of the men’s locker room completely naked.”

He did this numerous times “in the hopes of surprising another male officer who would then attempt to walk in and use the toilet,” the complaint says.

The former police chief, James Debbie, is accused of turning a blind eye to the alleged behavior and on some occasions, condoning the indecency.

Debbie, now the Mountainside Borough Administrator, is named in the suit — along with the mayor of Mountainside and borough council. The plaintiffs claim that the aforementioned parties refused to “effectively and appropriately” address the complaints about Murphy and Huber.

The cops were eventually placed on an administrative leave of absence, but not until after their higher-ups learned about the lawsuit.

Borough officials said Wednesday that they were approached back in February by Mountainside PBA attorney Leonard C. Schiro — who was representing the complainants at the time — and informed about some of the allegations. They launched an internal investigation and eventually decided to place Murphy and Huber on leave after the suit was filed on May 11 by the plaintiffs’ new lawyers, Charles J. Sciarra and Matthew R. Curran.

“The Complaint that was filed by Complainants’ new law firm contains allegations of current conduct that had not been mentioned by Schiro,” officials said. “In light of these new allegations and in the interests of avoiding the occasion for friction and discord in the Police Department the Governing Body has determined to place Officers Murphy and Huber on an Administrative Leave of Absence. Such action is not in any way designed to lend any credence to any of the allegations made in the Complaint. The Borough will continue the process of conducting thorough investigation of all the allegations in the Complaint.”

Mountainside Police referred all calls to Lt. Giannuzzi, who was not in the office on Wednesday night. Borough officials could not be reached for comment and neither could Sciarra or Curran.