The video for “Promises,” a 2015 song from Kid Ink and Fetty Wap, focuses on Kid Ink’s plans for a surprise wedding for his girlfriend. But about two-thirds through, the video grinds to a halt to show two boxes of Kandypens – a vaporizer mostly used to consume marijuana – sitting on a table, well-lit and arranged in a tableau so perfect that it could be at Macy’s (if the department store sold vapes). For the rest of the clip, almost everyone is using a Kandypen.

This extreme product placement for Kandypens (which you can also spot in Fetty Wap’s “My Way,” Migos’ “What The Price” and DJ Khaled’s “Do You Mind”) is part of a widespread love affair between rappers and marijuana tech companies. Snoop Dogg and Wiz Khalifa, who both have their own lines of weed available in Colorado and California, also have endorsement deals with the vaporizer G Pen. PAX, another vape company, put out a limited-edition collaboration with The Weeknd. Wu-Tang Clan’s Ghostface Killah has his own line of vapes through Dynamite Stix with the unappetizing name Wu Goo, while KandyPen works with a sizable stable of musicians and even has its own artist incubator program.

Given the natural affinity between rappers and marijuana, this might not seem shocking. But there’s a surprising legal reason that weed companies are pursuing so many endorsement deals with musicians: It’s basically illegal for them to advertise in any other way, even in states with adult-use laws on the books.

In California, Chapter 15 of Proposition 64, which legalized marijuana last fall, limits any advertising through broadcast, cable, radio, print or on the internet to outlets where “at least 71.6 percent of the audience is reasonably expected to be 21 years of age or older.” In Colorado, they cut weed companies 1.6 percent more slack: only 70 percent of the audience where they buy ads have to be over 21. Colorado also specifically outlaws marijuana-related pop-up ads, as well as advertising to “out of states persons,” meaning you can’t have a weed business in Colorado that runs national advertisements. In Alaska, anywhere selling weed “may have not more than three signs,” according to government regulations. And those signs are legally limited to a pretty reasonable 4,800 square inches, or 33 square feet (in Hawaii, which legalized medical marijuana, signs can’t be bigger than 11 square feet). Especially strange for something that is actually prescribed by doctors in more than half the states in America, weed producers in Alaska are prevented from claiming that marijuana has “curative or therapeutic effects.”

Perhaps most devastating, the two biggest players in digital advertising, Google and Facebook, both prohibit any advertising of marijuana or related products. Google considers marijuana a “dangerous product or service,” while Facebook has a blanket ban on advertising any drugs.

Standing out under these restrictions is hard, especially as the market is increasingly flooded with products.

“Anybody can go on [global trade site] Alibaba and find a supplier and put your name on it, and a lot of those companies have,” says Roger van Zandt, KandyPens’ Vice President of Sales, discussing how easy it is for a vape pen brand to launch. “It’s completely flooded with people that do that because they don’t focus on the brand. They just think, ‘Oh we’re gonna put out this pen and make a million dollars.'”

In this environment, many brands are investing heavily in endorsements and product placements, and a whole network of companies has popped up to facilitate the best possible partnerships. One of the biggest is Green Street, a full-service cannabis creative agency which has brokered deals for rappers like the Game, 2 Chainz and Snoop Dogg, as well as representing two of the world’s biggest weed festivals: Amsterdam’s Cannabis Cup and California’s Cannabis Chalice.

Green Street’s president, Rama Mayo, says that the key to making a successful partnership is connecting artists who care deeply about the product with a company that takes itself seriously.

“I think it’s the same no matter what the product is, whether it’s cannabis or not,” Mayo says. “The kids know what’s up. They know if you’re getting paid to sell something or if you really love it. It’s our goal to find artists and brands who really love each other. You want to find someone who actually uses the product, whose friends use the product, who’s down with the community.”

“He has so much knowledge,” adds Mayo of 2 Chainz. “We bring him the product, and he’s not even smelling it – just holding it in his hand and telling me about it without even putting it to his face. And his eyes are closed!” They approached him with two options for partnerships: endorse an expensive high-end weed that might move fewer units or a relatively lower quality product that might sell more? 2 Chainz picked the good stuff. After that, Mayo knew the types of products 2 Chainz likes and what kinds of deals to offer him. “He only wants to be fucking with these high-end brands.”

As for the companies, they’re just trying to get their product out there. “We have 12 celebrity endorsements,” says Kandypen’s van Zandt. “We’ve done over 35 videos, product integrations. We’re carried by the biggest distributors in the nation, and so we’re in all major storefronts, so when someone is in the market for a vaporizer, we hope that they’ll choose ours because of all the different places that they’ve seen it.”

Product placements like these “just work,” he adds.

Despite the noise from Washington, neither Mayo nor van Zandt seems troubled by their legal futures. For Kandypens, van Zandt points out that his company isn’t in the weed business; it’s an electronics company. “We’re in the picks and shovels business,” he says, meaning they make the tools and not the product.

Mayo points to medical marijuana’s long history in California – more than two decades – as proof that his company will find a way to cope no matter what happens. Optimistically, he thinks that weed is America’s new wine.

“You’re gonna see a Two-Buck Chuck, and also the most expensive shit of all time. You’re gonna see vineyards built around it. Sommeliers. The distribution is kind of similar,” Mayo says. “I’m not even joking. It’s insane money.”