Sitting cross-legged on a blanket in his Soho apartment, Barrett Pall inhaled toad-venom smoke through a glass stem pipe.

Thirty seconds later, he was crying.

“I was crying really hard, yelling ‘I’m so sorry’ over and over,” Pall recalled to The Post of his first time experimenting with the illegal psychedelic drug last year. (He’s since tried it twice more.)

“I saw my younger self with my parents and ex-boyfriends in places [where] I’d been hurt.”

The ­social-media influencer and life coach said the experience concluded after 45 minutes of “shooting through the universe” and “being reborn.”

Despite the trip’s short duration, the effects of toad venom — which is extracted from Colorado River toads, also known as Sonoran Desert toads — come on strongly and immediately. It leaves users immobile and unaware, and can cause extreme emotional reactions, euphoria and vomiting, according to drug researchers and users.

It’s also the hot mind-altering drug du jour among well-off New Yorkers, following the trendy trips of ayahuasca, mushrooms and mescaline.

One user described toad venom to The Post as “a total fusion with God.”

“It’s such an intense experience that, in most cases, doing it at a party isn’t safe,” said Alan K. ­Davis, a clinical psychologist and assistant professor at the Psychedelic Research Unit at Johns Hopkins University. “It’s not a recreational drug.”

But that hasn’t stopped psychedelic-drug lovers in New York City from seeking out the Schedule 1 classified substance, which carries the threat of a 10-year prison sentence for possession.

The toxic liquid is extracted by “milking” the toad’s poisonous venom glands, then drying it to a paste.

Users, such as Pall, score the extremely rare resin by hiring foreign shamans, often from Mexico, who travel throughout the US distributing it at ceremonies that cost $200 to $500 a head.

Recently, 21 people in white robes gathered at a mansion in the Hamptons to smoke the substance with the same shaman that Pall used.

While someone beat a drum in the background, the leader read a prayer about love and held the pipe up to each guest’s lips.

“Some people moaned, cried or convulsed on their backs,” said one attendee who asked to remain anonymous, citing legal reasons. “Others . . . started dancing, singing or chanting.”

Once the venom — also called bufo alvarius — wears off, users experience an afterglow that can trigger them to make major life changes.

“I immediately broke up with my long-term boyfriend,” said Pall, who also booked a trip around the world and decided to reconnect with his estranged father. “I was just so sure that everything I was deciding was right.”

But toad venom is not without its dangers. Some shamans operate “more like drug dealers” than spiritual healers and don’t properly look after participants, said Davis.

“If people get dosed too high, they can ‘white out’ and disassociate from their mind and body,” he added. “Anxiety can persist for days, and we’ve heard of people going to the emergency room.”

A controlled setting and well-trained chaperone are crucial, ­Davis said. He believes the venom could help with depression and anxiety.

About 80 percent of the 362 users he and his team surveyed for a new study reported feeling relief after using the drug.

“One of the hallmarks of depression is feeling disconnected and isolated,” he said. “5-MeO-DMT [the active ingredient] pulls you into something meaningful and makes people feel like they belong.”

At least for him, Pall says the impacts were positive: “My life has never been the same since.”