Trend sees men using iPhone's AirDrop app to share pictures of their privates on the subway

A disturbing new trend is hitting New York City's subway with women receiving pictures of creepy men's private parts via their iPhone's AirDrop app.

Britta Carlson, 28, was on the uptown 6 train on her way to a concert on 27 July when a strange message appeared on her iPhone.

The note said: "iPhone 1 would like to share a note with you," according to the New York Post. She hit "accept" and was distressed by what appeared. "It was a huge close-up picture of a disgusting penis," Carlson, of Brooklyn, said.

The message, which was titled "Straw," was sent by an anonymous stranger.

"It really felt like someone had actually just flashed me," Carlson said.

She told the Post that she held her phone close to her chest and frantically scanned the subway car for the man who had sent the message but could not spot him.

Frankie Navisch, 35, told the Post that he had just got off a train at Penn Station when he received a message to open "Eduardo's picture" with a preview photo of a man's private parts.

"Was he looking for interaction, or is all he wanted was someone to look at his mini-monstrosity?" he asked.

The trend was first reported in London in 2015. According to the Post, the AirDrop allows iPhone owners to share documents or photos with one another and uses "Contacts Only" as the default setting. However, the setting can be switched to "Everyone," which allows random people to send lewd photos.

AirDrop does not work with Android or Microsoft. People must also be within Bluetooth range, or approximately 328 feet (100m), for AirDrop to work. Apple has not commented.