ohrwurm - (n.) a song or tune stuck in your head [German]
"Luna? What are you humming?" Ginny asked suddenly.
The other girl looked up from her book, blinking her large, protuberant eyes. "Hmm? That song that they were singing at the Quidditch game, I think."
"...The one that the Slytherins used to destroy my brother's confidence and any chance that we had of winning the match?"
"I know, that was rather cruel of them, wasn't it? But the tune is very catchy, so I have a hard time getting it out of my head."
"Well, please try harder. Try—I don't know, humming something else. Sometimes I can manage to cancel out one catchy tune with another."
Luna smiled. "That's a good idea, thank you."
She went back to her reading, while Ginny went back to her Transfiguration essay.
A moment later, she winced as she heard Luna start to hum "A Cauldron Full of Hot Strong Love."
