When I went to the 40th Precinct station house in Mott Haven to report the man who had just masturbated to me on the uptown 2 train, an officer told me, “If you really want to get this guy, you should take it to the press.”

I think I will.

I was on my way to an assignment in The Bronx, and it was early enough that the train wasn’t packed.

I sat at the far end of the car, and I didn’t notice when he got on, but I did notice when he started pleasuring himself.

It’s impossible not to spot that sort of thing. He’d positioned his black backpack so the few others in our train car couldn’t see his hand vigorously moving up and down, but I could.

I could see his face, his hands, and other, more indecent, aspects of his anatomy.

He looked up — right at me — and I knew that he knew I could see what he was doing. He didn’t seem to care.

I’m a reporter, my gut instinct is to record. So I paused my music and switched over to video mode, capturing a 6-second clip as best as I could without escalating the situation.

I took a photo, too, that I hoped police could use to identify his face. And then I promptly picked up my backpack and moved to the other end of the train.

When I looked back, he was smiling at me. He was still doing the dirty deed.

At first, I didn’t think too much of it. This kind of X-rated subway ride had happened to me before, and to every one of my female friends. I’m under no illusions about how often this happens, even in such a public space.

But then I thought, I can do something about this. This guy picked the wrong girl.

There were no cops in the station when I got off the train, so I walked to a precinct station house half a mile away. I knew there wasn’t much the officers could do for me, but I wanted to report it, if only on principle.

When I told the cops what had happened, they were knowingly disgusted, telling me about other gross incidents they’d seen.

They dutifully filed a report for public lewdness and then sent me into Manhattan to the transit district office in the hopes their detectives could catch my particular creep.

The officers there had much the same reaction: They took it seriously, but there was only so much that could be done.

“There’s way too many of these guys out there,” one of the officers admitted. “We don’t always have the resources we need.”

So I don’t know if they’ll end up finding the man from my video, and that’s fine. It’s not about him, nor is it about me. It’s about not letting the behavior slide — and I’m glad I didn’t.

Anyone with information in regard to this incident is asked to call the NYPD’s Crime Stoppers Hot Line at 1-800-577-TIPS (8477) or for Spanish, 1-888-57-PISTA (74782). The public can also submit their tips by logging onto the Crime Stoppers Web site at www.nypdcrimestoppers.com; or on Twitter: @NYPDTips.