On one of the most frigid days this winter, the Hudson Park fountains were covered in snow and completely empty — except for the hundred or so people who were just about to take off their pants.

“It’s usually warmer — I was able to go golfing last New Year’s,” said Jesse Good, a senior agent at Improv Everywhere, who was helping organize the group’s 16th annual No Pants Subway Ride. “But the cold is better. In warmer weather, people might be in shorts — this creates more of an effect.”

The event, described by the comedy collective as an “international celebration of silliness,” draws hundreds of participants eager to kiss their bare flesh to a subway seat and the hundreds of species of (mostly harmless) bacteria that thrive there.

Every germophobe, and most New Yorkers, would call it a nightmare. But Bill Magner and Liz Dewey called it their second date.

“To be fair, I gave her an ample amount of opportunities to get out of this date,” said Magner, who explained that he had hit it off with Dewey over coffee on their first date. After happening on the event online, he decided to send her an invite.

Dewey had made up an entire story that she was moving so she wouldn’t have to participate. “I was nervous,” she said, but eventually she gave in.

After collecting in the park, the throng of riders packed into the 34th Street station of the No. 7 line, one of seven meet-up points for the event.

“Oh, I got to see this,” said one MTA employee on the platform. The conductor of the train poked out of his window and sunk his shaking head into his arms.

Pants-less participants filtered on at off at stops along their respective lines. And as they did they acted completely naturally — reading books, scrolling through their phones — as instructed by the organizers of the subterranean performance art.

Dropping trou in the subway was a bucket-list item for Ellen Capozzi, 70, who traveled from Toms River, New Jersey, to take part.

“From someone who survived the 60’s, sometimes you need to get a little crazy,” she said.

Eventually, the underwear-clad carousers converged on the Union Square station, where they danced to a band playing cover songs on the mezzanine.

“I can’t feel my toes,” said Wendy Wang, from Queens, “but I’m doing alright.”