There’s a double meaning in the title of Jordan Firstman’s rather wonderful feature debut, a coming-of-age movie about a boy now well into his 30s. Beginning 10 years ago before jumping to the present day, it shows a lifestyle so wildly hedonistic that the Greeks surely had a better word to describe it. Cocktails, cocaine, ketamine, not to mention tales of cock, plus cocaine-and-ketamine cocktails — this is the life led by New York party promoter Peter (Jordan Firstman), a promiscuous gay man who rules the city’s pansexual nightlife with his right-hand woman Sophie (Cara Delevingne). Luckily she shares his predilections: “What do we want? Drugs! When do want them? NOW!”

Everybody is dancing, snorting and f*cking, and Peter is so out of it he has sex with a British woman without apparently noticing. It harks back to a golden age, a ridiculously bacchanalian scene that must come with a best-before date; surely the center cannot hold? Time flies, however, and Peter is still up to his old tricks. “Do you ever lose 10 years?” he muses, as the setting moves to the present day.

Peter lives in a rent-controlled apartment left to him by his late mother, which he shares with a feckless roomie who plays X-Box all day instead of looking for work (“I’d love a job, but it has to be my dream job”). Peter’s hosting duties are getting out of hand, and most of his meager income comes from dealing drugs, making next to no profit on account of his habit of getting high on his own supply. Sophie, meanwhile, is making a more professional show of juggling business and pleasure, and after Peter turns up almost catatonic to an important meeting, she moves to dissolve their partnership. “You’re a drug addict,” admonishes the kettle, “and you’ve lost the plot.”

About to hit rock bottom, Peter is therefore oblivious to the +44 numbers that are blowing up his phone, until the caller — a British clubber called Edison (the fantastic Kirby Howell-Baptiste) — arrives on his doorstep. Like the stork, Edison is bringing a bundle of joy. Now age 10, Arlo (Reggie Absolom) is the precocious result of Peter’s intoxicated coupling with his late mother Leonora (Paris Petitjean), who since has taken her own life. Edison pops out to let them “get acquainted,” but instead she disappears into the night, leading Peter and Arlo to follow her into some very inappropriate places.

The comedy in this unlikely but still beautifully human story comes from Peter’s complete inability to comprehend parenting, the first inkling that he has a responsibility here is when Arlo — who digs The Cocteau Twins and Elliott Smith — innocently puts on a T-shirt that says “I Heart Bjork And Barebacking.” Truth be told, Arlo is too good to be true, being a trans ally into the bargain, and just when you start to wonder how all this is going to pan out, Firstman makes an elegant switch into a more serious tone, one that addresses all the questions you might have had about this man and his fitness to raise a kid.

It’s a difficult not to think of Adam Sandler in the wretched Big Daddy, but though it does mine a very rich seam of sentiment, Club Kid never settles for such schmaltz. Although the father-child relationship is very much the focus, Firstman uses the setup to explore other issues, notably the pressures of being a single gay man trying to extricate himself from such a transient environment. Its anything-goes approach to sexuality is intoxicatingly inclusive, and despite the loucheness of the denizens of the demi-monde, the film will strike a chord with any retired party animal who, as David Bowie once put it, suddenly realizes they don’t want to go out any more — they just want to stay home and get things done.

Title: Club Kid
Festival: Cannes (Un Certain Regard)
Director-screenwriter: Jordan Firstman
Cast: Jordan Firstman, Cara Delvingne, Reggie Absolom, Kirby Howell-Baptiste, Colleen Camp
Sales: UTA Independent Film Group (US), Charades (international).
Running time: 1 hr 59 mins