The thing about Murasakibara was that, although incredibly reliable during matches, he was endlessly lazy at any other given time (and more often than not in the matches, too, but his laziness in that area could be overlooked due to prodigious talent). He wasn't Aomine-level lazy; he at least did the courtesy of showing up to practices and training camps, but that didn't particularly mean that he put in any effort.
At least when Araki was around he participated, Fukui reflected glumly as he eyed Murasakibara's form, slouched over on the bench next to him and not listening to a word the gorailla was saying. (Araki was out with a cold; Okamura was full of bravado and leadership, which Fukui was determined to mock him for at some point). Actually, Fukui doubted that Murasakibara could have heard him even if he'd wanted to – he had earphones jammed into his ears and a faint, tinny sort of beating could be heard.
Some bench-warmer first years got up to set out plastic cones, eagerly directed by Okamura (who was really just pleased that they at least pretended to respect him; Fukui was coming up with vague insults already, he'd refine them while he was sweating it out), and Fukui took the break in activity to nudge one of their aces in the side.
"Did you even hear any of that?"
"Hm?" Murasakibara tugs at the cord of one earphone, the one on Fukui's side, and looks blandly down at him. (Fukui's a little bitter that even when sitting, even when slouching, those blank purple eyes are angled down, always down at him, from a great height he can't reach.) "Did you say something?"
"I asked you if you were even listening, but it's pretty obvious you weren't." He scowled. "What the heck are you listening to, anyway?" he asked, grabbing the fallen earphone and pushing into his ear (it's a little bit waxy and a lot warmer than he could be comfortable with; he winces when the purple head above him has to bob down to prevent his own remaining earphone being pulled out).
–But then he realises what he's actually listening to and he kind of wants to rip his own ears off. Or maybe Murasakibara's. Either way, flowing freely and loudly into his ear is the most cutesy sounding disgusting crap he's ever heard. It's all... poppy and upbeat (and totally not Murasakibara, who acts and looks just as morose as a funeral march) and he thinks that it's terrible and realises he was wrong once he picks up the lyrics: it was a nightmare. These words would go one to haunt him for at least a fortnight, and he seriously regretted being fairly adept at English.
CANDY CANDY CANDY CANDY CANDY
SWEETIE SWEETIE GIRLS LOVE
CHEWING CHEWING CHEWING CHEWING CHEWING
CUTIE CUTIE CH-CH-CH-CHEWING LOVE
Closing his gaping mouth slowly, Fukui removed the earphone, staring straight forward, and eased himself upwards. He didn't say another word for the rest of the practice (he heard Okamura murmuring to Liu concernedly about it but couldn't be bothered to comment).
Afterwards, he poked around the storage room, hoping to maybe find a spare shinai of Araki's to that he could beat the memory out of his head; he comes up empty though, and is a little relieved that his head is spared and a lot disappointed that amnesia isn't a feasible option.
(It's not until he gets home that he realised that he had forgotten to insult Okamura.)