"How do you feel about the violin?" —Sherlock Holmes
The violin was a problem.
It would start out normally enough. There was melody, it was in tune, it sounded like—here John felt his lack of facility with classical music—like it belonged in a concert, damnit, like violins were supposed to sound. It swooped up and down, it marched, it sang.
But then, always, it would change. It became repetitive, dissonant, even rough-sounding, as if the bow were not being used quite properly. Yet even as it started to fall apart, it would be building. The one thing that never faltered, at this stage, was the rhythm. In fact, it tended to become more insistent, to speed up just a bit, for the strokes to fall more heavily on the beat.
The entire performance was unsettling. If John hadn't fled earlier, this was the part that would drive him from the room. Somehow it seemed wrong to stay; if he attempted it, his ears burned, he didn't know where to look, he couldn't concentrate on anything without the insistent music breaking into his thoughts. And he certainly couldn't watch Sherlock. Sherlock's eyes would close, his mouth drift open, his body bend back or rise on its toes. His face looked naked. It was indecent.
The third stage, he was never present for. This was where the music would lose all coherence, turn ragged, stutter to a stop. John didn't want to know what Sherlock's face looked like when that happened. He tried not to imagine it. He tried to stop imagining it.
He couldn't stop thinking about it.
Gradually he began to suspect something incredible. Un-credit-able. Something he couldn't believe. He needed to be sure.
The next time Sherlock began to play, he tried to make himself stay to the end. He sat, rigid with awkwardness, glued to his seat as the music became driving and dissonant. Sherlock was wearing the pyjama bottoms, which John knew could not hide a thing. (He knew this from personal experience. If Sherlock's clothes were going to mysteriously turn up in John's laundry, hitch a free ride to the laundromat, they could damn well expect to be—well. Worn.)
He sneaked a glance. There was nothing to see. Nothing but the arch of Sherlock's back, the movement of his hips, his face evolving into a rictus of—no, he wasn't meant to see this. It would be wrong for him to see this. John fled.
Behind him, the music faltered into random strokes. He could’ve sworn he heard a gasp.