When it comes to subway etiquette, some rules are clearer than others: for example, shaving your head on a crowded C train is a clear no-no, while watching a feature film sans headphones may be slightly more up for debate. And true, the line between feature film and pornography can be a bit blurry sometimes—but just to be on the safe side, maybe wait to watch your erotic videos until you get home, lest you incite the wrath of a Gothamist tipster.

We got this tip from a female subway rider who wished to remain anonymous, who said that she was on a Manhattan-bound 4 train in the Bronx early this afternoon when she noticed this man (the one wearing glasses) watching an X-rated video on his phone.

"The video was of someone getting a massage and from what I can tell, it really quickly got oily and pornographic," she told us. "When I first looked up, the video was pretty clearly of someone laying down and getting a massage, and I remember thinking 'what a weird thing to watch, oh fuck, is this going to turn into porn?' And then sure enough, whatever towel/shorts situation was happening over the person's lower body got pushed down and it totally turned into weird oily massage porn."

She said it seemed like the guy wanted other people to see his screen. He "wasn't even watching, but was holding it in a way that he was trying to get other people to see it," and he reportedly kept glancing around to see if anyone had notice. But she said that no one else on the train did appear to notice, perhaps because, to his credit, he either had the volume down or off completely.

The woman who noticed got off the train shortly after realizing what was going on, but says that by the time the train had reached 125th Street, he'd put the video away. She reported the incident to the MTA, which has previously stated that watching porn on the subway violates its code of conduct and encourages passengers to report such incidents to the MTA, the police, or 511. The MTA didn't respond to request for comment on this particular incident.

"I know it's not quite the same as a subway masturbator, but it still seemed pretty gross—if not illegal, very bad subway etiquette—especially since from his position he was clearly trying to get other unknowing people to watch it," she told us, adding, "At least the guy himself kept his pants on?"

Indeed—it could have been worse.