J.K. Rowling gets into it on Twitter with Tinie Tempah, the one rapper who apparently studied at Hogwarts.
She's referring to Tinie Tempah's new single, "Girls Like," which features the refrain, "Tell J.K that I'm still rolling." This has little to do with anything girls actually like and more to do with Rowling's last name sounding like the drug and general fun-time phrase, "I'm rolling." Rolling/Rowling was nonplussed:
You hear that? It's the sound of Tinie Tempah's cue to prove he can go toe to toe with anyone on Harry Potter: