Joshua Castro is whipping around so fast, his skateboard wheels are making a whooshing noise like traffic on the BQE. He pushes his board up the side of a 6-foot wall, building up speed to get around the entire bowl.

Then the 23-year-old bails — but the 15 other skaters awaiting their turn on the lip clap their boards against the wood floor, the skater version of applause, while music by the heavy metal band the Sword blares from the sound system.

The borough that’s already pushing the envelope on pubs — there are watering holes where you can play minigolf or shuffleboard — just added a skateboarding-bar mash-up.

Black Bear Bar, the city’s first beer-and-boards spot, opened in January in Williamsburg — with a skating bowl about the size of a small in-ground swimming pool.

Part action park, part theater, Black Bear’s attracted dozens of skaters a day looking to show off their moves — often in front of a rapt crowd sipping beers and cheering behind a garage door with windows covered by chain-link fencing that serves as a divider.

The skaters are mostly 20-something dudes, but women and the occasional gray-haired skater are also in the mix.

“Oh man, this place is f - - king gnarly,” says Castro, of Ozone Park, a skater since 14, shaking off a spill. “There’s not really much going on indoors in New York City. We got the worst weather, too.

“We need some more indoor s - - t. That’s why I’m really hyped on this thing right now.”

Owner Jessica Wertz describes her place as “almost like an installation or an exhibition. Except it’s a skate bowl.”

She got the idea for installing the bowl after talking with skater friends and realizing the front room — previously a motorcycle showroom — was being underused.

Skating under the influence is strictly forbidden, with the bar employing a monitor to watch over the bowl and keep out sloppy skaters.

Skaters sign waivers, and a minimum of two years’ experience is required. Only people 21 and over are allowed in — though occasionally kids can skate, too, if their parents come along. Skating is free, usually from 6 p.m. to 2 a.m.

On one recent weeknight, a 22-year-old from The Bronx who skates under the name Viva Wonderland says she isn’t fazed by the cold, but the icy streets drive her inside.

“In summer, I would definitely come here if it’s raining,” she says. “Or if I just want to have a drink, I’d come and chill and watch other people skate.”

That’s what the bar’s owners had in mind when they built the bowl, in partnership with Levi’s and skating brand HUF. Black Bear is adding skating exhibitions to regular live music and DJ nights.

“It’s fun when you can drink a beer and see your girlfriend or boyfriend rip it in the bowl,” Wertz says. The crowd was getting into it when another female skater joined Wonderland.

A woman watching in the bar screamed “Girl power!” from behind the fence. The skater looked back and smiled.

For some, though, those cold Tecates might be a little too tempting.

“I still wish they would just let me drink and skate,” says Anthony Carpenter, 27, after a few rough wipeouts. “Then I won’t feel it anymore. Drink the pain away.”