Hotels stand on The Strip in this aerial photograph taken at dusk above Las Vegas, Nevada. Pic: Bloomberg by David Paul Morris.
In Las Vegas there's no better byword for sophistication than the Cosmopolitan. Its 20-plus suites, known as the Boulevard Penthouses, are the most coveted rooms in town, largely because they're priceless. 

The only way in is by invitation, which means fronting over a million dollars (and preferably two) at the Reserve, the hotel's private, three-room casino on the 75th floor. It's a gaming experience so exclusive that not even James Bond could charm his way through the door.

When the resort offered me a staff position serving its penthouses' high-rollers, roving from butler to bartending stations and everywhere in between, I  was initiated into the secret realm of the Reserve, catering to the whims of the world's wealthiest gamblers. 

Think what happens in Vegas stays in Vegas? Not this time

It's a judgment-free zone where people can come and behave in an extreme manner.

Some big spenders push this to the limit. One repeat guest prefers the suite with a chinchilla-fur hammock; he's been known to splay himself across it naked, waiting for a butler to find him. 

A well-known basketball player, enjoys having sex on the morning of his departure while the butlers fastidiously pack up his luggage. 

One of the casino's oldest guests-also one of the only high-rolling women-has garnered a colorful reputation for discarding fur coats and throwing fists in the gaming salon when her luck is waning. Her other favorite pastime: asking the butlers to dress up in pajamas, crawl into bed next to her, and read her bedtime stories. 

Welcome gifts can include obscure objets d'art or vintage Chanel; the hotel has even hired a full-time chocolatier to create custom-made, edible sculptures inspired by a guest's Instagram account.

Room service tastes of big-spender guests. 

Standard orders range from green juices to fresh seafood picked out via webcam from the casino's private aquarium.

Regular trips are also made to Chinatown emporiums that peddle a witch's brew of rare teas, herbs, and-strangest of the bunch-cordycep worms -  a type of caterpillar-eating fungus that gets hand-picked in the Himalayas and sometimes used like Viagra. They're literally worth their weight in gold.

Baccarat is the prevailing game of choice.

First, it's familiar to more than 50%  of Reserve guests who hail from Asia and play it in Macao. 

The casino's biggest Baccarat bet to date was $300,000 per hand for 8 decks of cards, played out as roughly 60 hands in 60 minutes-on two tables simultaneously. Those are stakes of roughly $600,000 per minute, or $36 million per hour. 

The biggest client victory witnessed amounted to $30 million over a short weekend trip.

Exotic Requests: 

As an animal-friendly hotel, the Cosmopolitan fields a lot of pet requests.  But dogs aren't the only pampered critters in Vegas. A misbehaving sugar glider (aka a flying squirrel) with severe separation anxiety takes the prize for weirdest animal guest, while nocturnal snakes that required dozens of blackout shades might be the highest-maintenance.

Things get crazier when animal requests revolve around wild creatures, rather than domesticated pets. Once, someone asked for a monkey to be dressed up in a butler's uniform to check the guest in. 

Some things are off limits, even in Sin City: 

In the category of demands that can't be fulfilled: hookers. The thinly veiled requests, however, come roughly once a week: "Can you introduce me to someone?"

Requests for drugs-usually cocaine-are also once-a-week occurrences.

Courting lady luck with a dose of superstition: 

Among high-rollers, superstitions can quickly escalate from the demanding to the absurd. Some millionaires will sleep on the couch because they believe a bed with a headboard will beckon bad fortune. 
Others crown themselves with citrus-often with holes poked to "unleash the luck"-scattering pierced oranges and lemons around the suite, letting them rot during longer stays. Also lucky for clients from the Far East: filling water basins to the brim. 

Tips that tip the scales: 

Seven-figure bets often mean sky-high tips. It's standard for a weekending penthouse guest to leave between $300 and $500 for housekeeping-plus a few hundred dollars a day for the butlers. The record-setter, however, was a $40,000 gratuity for a couple of days of service, left by a famously generous repeat guest. 

High-rollers who take things home.

When a guest loses a million dollars in the casino, they want their million dollars back.  Artwork, duvets, even bathroom scales are stolen.

Several have brought extra suitcases and asked the butlers to fill them with items from their suite-think coffee table books, unopened alcohol, and decorative Hermès knickknacks.

Turns out, even if you lose big at the casino, the hotel has its ways of making you feel like a winner.