Pour a stiff martini, slip on a turtleneck sweater and step into the sleek Rat Pack world of American pop artist Josh Agle, better known as Shag.

His Atomic Age-style paintings of beatniks and hot housewives bustle with 1960s tiki lounge-lizard chic and sophisticated poolside parties, in scenes where menace lurks behind every corner – crocodiles dine with rich old dears, executioners guard croupiers in Las Vegas, and Bond girls sink nightcaps prepared by skeletons.

But these artworks aren’t the stuff of fantasy. Lean and clean-cut, the artist who’s sold paintings to Seth Green, Rob Zombie, Whoopie Goldberg, Courtney Cox-Arquette and Lisa Kudrow admits that most of the angular characters in his work are incarnations of himself, and his hard-drinking creativity comes from his grandfather, Lawrence Suman, who was a successful commercial artist in the 1930s and 1940s.

“My grandfather set a precedent in my family,” Shag says. “Because he was hard-working, he made it acceptable for me to aspire to a career as an artist. But he was also stern – not at all ‘grandfatherly’ – and drank a bottle of wine a day. I was afraid of him and tried to avoid him as much as possible.”

As a child, Shag often visited his grandparents at their estate in Sierra Madre, near Los Angeles. Lawrence lived in one wing of the house – away from his wife and visitors – and kept to himself until he’d sunk half of his daily bottle, only venturing out in the evening to socialise.

“For better or worse, there are aspects of his personality that I share, though I’ve tried to fight them,” Shag says, “People who know me from parties are sometimes put off by ‘Sober Shag’, who seems sullen or serious compared to ‘Social Shag’.”

For Shag, the road to happiness is lined with tiki and Dionysian decadence. “The tiki thing resonates with some sort of genetic connection I have to my primitive ancestors: the unfettered sexuality, lack of societal constraints and giving in to our hedonistic impulses,” he explains.

Shag’s obsession with tiki culture is all-pervasive. As you explore his house, you’ll find more than 400 tiki-style mugs – dozens in his otherwise minimalist studio, and the majority in his dining room. “I’ve confined them to a few areas, rather than making my house look like the interior of a branch of Trader Vic’s,” he says. “I love the way tiki joints look, but I don’t want to live in one.”

Shag’s love affair with hula tropicana began when he started drinking in his early twenties. He and his friends loved tiki bars and they sought out the places in LA that had the best booze and ceramic mugs. “What started out as a souvenir collection from a night of drinking became an obsession,” he says. “My friends and I tried to outdo each other with the tiki memorabilia and mugs we were able to find in thrift stores and flea markets.”

But when it came to creativity, no-one could outdo Shag. In the 1980s and early 1990s, he played guitar in several bands, including The Swamp Zombies, The Huntington Cads and The Tiki Tones, and produced the artwork for their records.

Other musicians loved his work and he was quickly asked to design record sleeves for Spoon, Satan’s Pilgrims, and a Sex Pistols boxset. He assumed that’s how he’d continue to make a living but, in 1995, his friend Otto Von Stroheim, publisher of Tiki News magazine, booked him for a gallery show.

“It was just one wall in a tropical-themed coffeehouse in Santa Monica,” he says. “Since my work up to that point had been commercial, I had to imagine the kind of thing I’d like on my own wall: it involved tiki and drinking, and would be based on commercial art from the 1950s and 1960s.”

Shag’s paintings for that show were a hit, and since then his work has sold as quickly as he can create it. Today, he’s picking up the clients he wants, and his biggest coup was a commission from Disneyland to make the official collectible art celebrating its 50th anniversary.

Shag’s Disney-mad. He lives a 15-minute drive away from the park, owns a premium annual pass that gives him year-round access, and cherishes a strong family connection: his grandfather schmoozed with Walt Disney in the 1930s and 1940s and was given VIP passes to Disneyland before it opened to the public in 1955.

“Now, they treat me like a VIP!” he beams. “I love the design in Disneyland – everything is put together so well: the attention to detail is amazing, and the place is kept spotless. It also touches upon themes I always return to in my artwork: tikis, monsters, space and pirates.”

One job on Shag’s wish list is a collaboration with a high-fashion designer such as Chanel or Louis Vuitton, although he admits that it’d just be an excuse to hang out with supermodels and lure them back to his lounge-lizard home.

On a private road in the hills, Shag’s house is deliberately impossible to find so that uninvited guests don’t gatecrash his soirées. It’s inspired by Blake Edwards’ film The Party, in which Peter Sellers plays a fish-out-of-water dinner guest at a 1960s pad filled with showy water features and push-button retractable furnishings.

And, while Shag’s sofa doesn’t pop up by remote control, he does have a 15ft faux-rock waterfall outside cascading into a swimming pool surrounded by orange lounge chairs, picnic tables and parasols. It looks like a summertime oasis, even on a dull day.

Shag’s got another waterfall outside his dining room that he wants to connect to the pool via the middle of his living room. Inside, the minimalist house oozes 1950s modernism and everything has its place.

Guests are always offered a drink, and, unless they opt for a soft one – which the maid will make – Shag’ll fix it for them while playing with his home-made Wheel Of Fortune, or palm reading machine.

The bar is a soak’s paradise. “When I was in my late twenties, I decided I needed a fully stocked bar in my house,” he says. “I wasn’t sure what to get so I consulted Seagram’s Bartending Guide, and followed its recommendations. It cost me almost ,000 (£700), but since then, keeping it stocked has been my priority, and I’ve got everything I need to make most standard cocktails.”

Although Shag says ‘yes’ to most drink requests, many of his bottles are hidden in a cabinet. “The party and the type of people coming determines what sort of alcohol I put out,” he explains. “I don’t want my wife’s theatre friends drinking my 1968 Crown Royal.”

A party at the Shag residence can be anywhere from five to 200 close friends or fellow artists, but, even though Shag regularly gets wasted, he rarely has hangovers. “I usually end my evenings of drinking with a couple of shots of good vodka,” he says. “For some reason that seems to take care of things.”

Shag either works or drinks, so he surfs twice a week to maintain his sanity. “The only other time I get off is when I travel for shows or commissions,” he says. “But then I like to go to bars, pubs, lounges and cocktail parties. One of my friends told me, ‘It’s not that you drink a lot, it’s just that you never pass up an opportunity to drink.’”

If Shag ever loses control, it happens when he’s away. Once, in Ohio, a stranger offered to drive him home after a heavy session at the world’s largest tiki bar, the Kahiki, and Shag puked in the car.

The last time Shag was in Tokyo, he blacked out after drinking Shochu, a rice-based Japanese vodka, with his brother. Unbeknown to Shag, he snogged a life-sized plastic little girl – the mascot for Pocky sweets – outside a shop, then tried to karate-chop his friends. “I didn’t believe my brother when he told me what I’d done,” laughs Shag, “but he pulled out his iPhone the next morning, and sure enough, he had the photos to prove it.”

But don’t be fooled. Even though Shag’s life is resplendent with travel and partying, he’s a workaholic. “I get up between six and seven every morning, no matter how late I was out the night before, and start painting immediately,” he explains. “I get my best ideas in the morning. Depending on my mood, I might paint until six in the evening, then go out with friends for dinner or drinks, or I might stay in and paint until one in the morning – mixing myself a cocktail at nine to keep the ideas flowing.”

Shag also hangs out with his family. He has an 11-year-old daughter and a seven-year-old son with his wife Glen, a theatrical director, who likes socialising even more than he does. “I like being a father,” he says, “it makes me   feel like a kid again, and my children know more dirty jokes than all of the other kids their age.”

They may well be telling them over a Cosmopolitan soon. Shag’s next plan is to launch a line of hard alcohol for 10-year-olds.

“I intend to create the advertising and imagery, the marketing materials and toys to accompany the brand – everything but the alcohol itself,” he smirks. “Maybe 60 years from now, people will discover the toys or ads in thrift stores and flea markets, and be aghast that someone in the early 21st century targeted little kids for drinking…”