After Kevin Durant announced that he was going to sign with the Warriors back in July, Twitter exploded with everyone from casual NBA fans to NBA players weighing in on KD’s decision. KD’s longtime Thunder teammate Russell Westbrook reacted, too, but his reaction didn’t come in the form of an "OMFG" tweet or an angry Facebook rant. Instead, Westbrook responded to the news by posting this photo on Instagram:

Cupcakes? Cupcakes. It was an odd reaction, to say the least, and it had quite a few people guessing as to why he chose that moment to post that photo:

As it turns out, there was a good reason for it. Lee Jenkins just wrote an excellent cover story about Westbrook for Sports Illustrated:

And in the story, Jenkins broke down how Westbrook was playing dominoes at a 4th of July picnic when he found out that KD was leaving Oklahoma City. According to Jenkins, he responded by, well, playing more dominoes—and by posting the now-infamous cupcake photo. And as Jenkins writes, there was likely a hidden meaning behind those cupcakes:

Westbrook and Durant were not best buds, but they were peerless partners, a souped-up Stockton and Malone, transporting a mini market to the big time. Westbrook’s closest friends are actually former high school teammates, long-standing wing men like Donnell Beverly and Demetrius (Juice) Deason, who flank him in summer pickup games and play dominoes with him on the Fourth. “He didn’t talk much about what happened,” says Beverly. Westbrook didn’t disparage Durant. He didn’t judge him. All he did was take a picture. When Kendrick Perkins played center for the Thunder, he called teammates "cupcake" if he thought they were acting a little soft. Westbrook and Durant adopted the term in jest. Westbrook posted a bittersweet pic on Instagram: three plates of cupcakes topped by red and blue stars and sprinkles.

And just in case you need proof that KD and Westbrook do—er, did?—call each other "cupcake":

Whoa. Nowwwwwww it makes sense.

It’s just one of the many gems you’ll find buried in Jenkins’ story on Westbrook, which features lots of anecdotes about the Thunder superstar. When you read it, you’ll find out why Westbrook loves calling those close to him "asshole" or "piece of shit," what he did immediately after re-signing with the Thunder in July, and how he’s going to approach the game of basketball now that he’s the face of his franchise. You can read the entire SI story here, and if you missed it, there’s also a new KD Rolling Stone cover story out today that you can read more about here.