5 Times John sings, 1 time Sherlock sings.

It's just something he's always done. Ever since he was quite young, through his school, college, university days, even during his time in the army (much to the light-hearted hilarity of his colleagues) he just couldn't keep himself from singing in the shower.

It wasn't that he thought himself a particularly good singer, and had nothing to do with the fact that he knew the humidity of a hot shower created the perfect environment for singing – it was just the one thing that truly relaxed him… In particular since he returned from Afghanistan. He found the petty, superficial issues spewed from his tiny portable TV on a daily basis only served to twist his inside into a huge, burning knot of rage. Damn it, he wasn't MEANT to be slouched in an armchair watching Jeremy Kyle, he just…knew it. Felt it. He was meant to be in control, making life-changing decisions, doing what he had worked so hard to do, saving lives…if only he could get from one side of the room to the other without having to cling to the furniture for support. If only the ugly scar on his shoulder would fade to nothing, the muscles fibres knitting back together overnight, leaving him good as new, ready and raring to go. If only, he thought to himself with a sneer that sat uncomfortably on his face. The worst thing was knowing with the devastating clarity of a medical professional that just wasn't how it worked.

Walking, running, trying to be active – things that used to give him some clarification of mind and lift his mood… now left him feeling as wound up and frustrated as being stuck indoors. The pitying glances – stares – that followed him everywhere from complete strangers were torturous, let alone encounters with people he had known. The roars of joy and anger from a rugby field used to bring a nostalgic smile to his lips – now they taunted him. Another little hobby he had merely enjoyed but never taken seriously, another thing he ached to be able to do one more time.

He certainly didn't look for relaxation or comfort from a hot shower at the end of the day. It was a necessity, although his time in the army had taught him to properly appreciate those little comforts – a cup of tea, a digestive biscuit, a soft pillow…and now, the warm water beats on the back of his neck and across his tight shoulders, massaging away the knots born from holding his injured shoulder awkwardly, or having to lean heavily on his crutch when his leg decided to play up. A few minutes of blissful normality and relief. A little while of remembering how to be optimistic, hopeful, even.

He sometimes isn't even aware that there is a song tumbling from his lips, at first. It comes to him as naturally as breathing in and out.