Sherlock Holmes plunged his head underwater and marveled. He knew, of course, that sound moved more quickly through liquid than air, and that immersing oneself ought to make sounds louder, carry farther. What none of the books mentioned was the simultaneous muffling of the world.
The water became the world. It became the sensation against his skin, it emptied his sight to a dull and murky enclosure and then forced his eyes closed when the burning became too much. Sound was both amplified and muffled and confined to within the pool. There was no smell at all because there was no breathing though he could still taste the chlorine on his lips. It was peaceful. Even with the way his heart beat faster and his lungs began to burn and he had to burst his head back up and suck in the world again.
"Good, very good," John said as his head came back up, his voice calm and just barely managing to not sound condescending, like he was speaking to a toddler taking its first dip. Sherlock said nothing in reply, still studying the feel of the water, of the cement beneath his legs that contrasted sharply with the billowing softness lapping gently against his chest. The bathing suit shorts which had felt a bit confining when he put them on now felt almost too loose, billowing with the water. It was fascinating.
"Do you want to try going deeper?" John asked and Sherlock considered it. So far, his swimming experience had not been nearly as unpleasant as he had thought it would be. He had wanted to learn more to overcome a somewhat embarrassing fear and to learn a valuable skill, approaching it like a chore or one of his more odorous experiments; something that needed to be done no matter the unpleasantness. Except the water wasn't unpleasant. It was big, and wet, as he had expected, and it made his heart race as he sank into its depths in a partly terrifying, partly thrilling manner. The sensory deprivation offered with the simple act of dunking his head was intoxicating in itself, both encompassing the worst of his fears and yet offering complete peace in from a world that was often all too noisy, bright, rough.
And John was there. John was always there. John was a solid, warm presence that wasn't going to let the water swallow him.
"Yes," he said at last, "Alright." And they stood from where they sat upon the steps and waded out together.
"The air feels colder than the water now," Sherlock remarked thoughtfully as the water slid higher with each step, and the bathing suit went from clinging uncomfortably heavy and wet to his legs, to billowing and loose once more as the water went up to his waist, his chest, towards his shoulders. They stopped when the water reached John's chin.
"Alright…right," John said, after they had stood there a moment and Sherlock hadn't panicked, "Do you want to try some swimming moves?"
"Alright," Sherlock answered, and then uncharacteristically waited to be instructed. John, being the sensible man he was, started with treading water. Sherlock copied him, his mind going over everything he knew about surface tension, buoyancy, and weight dispersement as he spread out his long arms and ran with his legs in an imitation of what John told him to do. And the water held him up. Not that he expected the water to drag him down where the rules of physics would cause any other man to float, but it was one thing to expect a certain result and another thing to feel it happening.
"Is this all there is to swimming?" he asked, "I would think anyone could figure it out for themselves after falling in."
"People panic," John pointed out. John was looking at him in a scrutinizing manner, though what he was attempting to deduce Sherlock was not certain.
Floating came next, another easy lesson, and then John wanted him to imitate a dog and paddle from one side of the pool to the other, still in the shallower end so he was never over his head. John suggested leaving the rest of the lessons for another day after that, now that they both knew Sherlock would be able to keep his head above water if the need arose.
"Don't be ridiculous, John," Sherlock answered, "I want to swim properly, not splash about like an infant." Despite his words, he looked rather proud of himself as he half floated and half paddled to the side.
"Right then." John answered, smiling at him and appearing rather proud himself, making Sherlock want to go twice as far, all the way to the deepest end and back again, just to show he could. "Let's try underwater next."
"First rule, don't swim right towards the side of the pool," John began, then paused before adding, "Unless you hold one hand out, so you don't hit your head."
For a moment, Sherlock felt cold and wet and that the pool was far too big and deep and empty, and John was looking concerned again.
"We can stop now," he reminded him, and Sherlock shook his head sharply, his wet hair clinging uncomfortably at his neck and throwing droplets across the water. He forced himself to calm.
"I'm ready, John," he insisted. John still hesitated for a moment, but then told him that they were going to swim like frogs before he ducked under water and showed him.
Swimming beneath the water turned out to be nothing like swimming over one's bed. There were no sheets to get tangled with, nothing beneath one's stomach at all, and water resisted in ways that air didn't. It was fantastic, a bit like flying, and terrifying because water was the entire world and any moment he was going to hit porcelain and the hands were going to hold him down and the water would burn into his lungs. Sherlock didn't last longer than five seconds before he had to burst up again, gasping in the outside world beyond the pool and water and hands.
He stubbornly tried it close to ten more times, ignoring John's suggestions and then demands that he take a break, until he managed to more or less swim from one edge to the other, minus a few feet at either end.
"Enough," John said, "We're taking a break."
"Show me the kicking kind of swimming," Sherlock answered. John was staring at him, his look of concern uncomfortable and completely different from his warm smiles and proud look from before. With a sigh, John led him to the edge and they practiced kicking.
Combining kicking with moving his arms created more splashing than forward movement, and that look in John's eyes relaxed and he was smiling again, which made something in Sherlock's chest feel lighter. John made no suggestions about Sherlock putting his face in the water as he swam, even though he had explained that part back in the flat when they practiced on the bed. Sherlock supposed he ought to be annoyed, except he didn't see the point in it anyway; he had no difficult staying afloat with his head held firmly above the water and he saw no need to try it the other way.
Learning to swim also apparently involved more touching than swimming on the bed had needed. John put his warm, strong hand against his chest, pushing him upwards, encouraging him to glide over the water more than under it.
Still, knowing how to swim was only half the reason he had agreed to come. Ignoring the way his heart beat sped up, Sherlock decided there was no point in easing from the shallows now. Pushing away from the side determinedly, he moved out towards the deep end.
"Sherlock," John called, but didn't say anything to really call him back. Sherlock considered answering, but it took quite a bit of his breath to swim. It also took just enough brain power and concentration that he thought about that and not the depth of the pool or water swallowing him whole or heads connecting with rocks or porcelain.
He touched the wall of the far end and paused, feeling the awkward sensation that his feet couldn't feel a ground no matter how they stretched. It was curious as much as it made his breath hitch. Determined and somewhat curious, he ducked his head under, leaving only one hand out to clutch the side of the pool. The water rang in his ears, his hair flying wildly about his head, and he was empty and lost and alone.
Then he burst free from the water, with a laugh of triumph, looking back at John where he waited, ready for action if necessary but giving Sherlock room to experiment on his own.
With no hesitation, Sherlock pushed away from the wall, completely out of his depth and still breathing, and he paddled and splashed and kicked back again. John was waiting there to greet him.
For real this time.