"John. How do you know that you love me?" Sherlock turned to John and said, still breathless from his very recent orgasm.
They were naked in Sherlock's bed, after a bout of mutual masturbation, as Sherlock calls it, or bloody fantastic sex, as John calls it. John smiled indulgently.
"How did you deduce that I love you?"
"Obvious. You care for my well-being in all situations, prioritize me above all else, forgive my faults, admire my intellect, and display biological marks of arousal in response to my physical intimacy."
"There you go, then."
"That doesn't help!" Sherlock hissed, punching the pillow in a sudden display of petulance.
"Help what?"
There was a sullen silence. John was prepared to let it go and drift contentedly into sleep, but just before he did, Sherlock's voice jerked him awake again.
"It doesn't help me discern whether I love you."
John turned to him, blinking. Sherlock lay on his back, the contours of his pale, angular face illuminated by streetlight, looking thoughtful and conflicted.
"I am given to understand that it is immoral to lay with someone that loves you if you do not love them in return. I don't do any of those things that you do for me, John. I am not a good man."
John's stomach fell out, leaving an aching, empty space, and he reached for Sherlock, pulling until his arms were filled, and they were pressed into each other skin to skin, Sherlock's every breath and vibration echoing into him.
"People show love in different ways, Sherlock. What do you feel?"
Sherlock made a rude noise. "You know sentiment is not my area."
"Love is a sentiment."
"Exactly the problem, my dear doctor."
"Why are you so bothered, anyway? It's not like I've been pressuring you to say it back."
"I don't want to take advantage of you, John."
John huffed a laugh. "Trust me, you're not, okay?"
"You're a terrible judge of that. Biased. I need to design an experiment."
With that, Sherlock jumped up and shot out of the room, presumably to start designing his experiment. The next day John noticed a lot of odd search terms in his google history, such as 'characteristics love' and 'biological markers love'. He smirked and shook his head.
John went to work as normal, and texted Sherlock during his lunch break.
Man came in convinced he was a hedgehog. Was quite insistent. –J
The reply came more slowly than usual.
Trying to get sick note for work. –SH
John grinned.
Probably. What do you want for dinner? –J
Busy –SH
Busy trying to tell if he loved John? That would be far less destructive than his usual experiments. Unless, of course, Sherlock concluded that he didn't. But honestly, John wasn't that worried. The fact that Sherlock was worried about it at all more than proved that he had a heart.
Late in the evening, long after John had finished his dinner and was sat at his desk tapping out a blog post on their latest case, Sherlock stormed in, face alight, coat billowing, looking as if he had solved a case.
"John, I love you."
A slow smile spread across John's face.
"Yeah? I love you, too."
Sherlock frowned, looking confused and impatient. "Yes, I know that. Now- "
"Wait, wait, wait," John interrupted, exasperated. "'Yes, I know' is not an appropriate reaction to a confession of love when you love someone back."
"Oh. But I did already know that, and repetition is dull."
John stared at him.
"So you only liked it when I said I love you the first time?"
"Well, yes."
"But you'd deduced it already."
"You were confirming it."
"So you don't care if I never say it again?"
"Why would I?"
John spluttered. "I- I don't know! My feelings could change!"
At the look of utter alarm on Sherlock's face, John quickly amended, "Hypothetically."
Sherlock only looked more alarmed.
"Look-does that mean just now was the only time I'm ever going to hear that you love me?"
"I could say it again. Would it have a stabilizing effect on your own affections?"
"Er- it's nice to hear."
"Odd. Can't you just assume that I love you until such time as I inform you otherwise?"
John rolled his eyes to the ceiling, at a loss for words. Typical. Of course Sherlock Holmes didn't have a drop of romantic blood in his stupidly fit body. John didn't know what else he should have expected of the man who had kicked off their sex life by buying three boxes full of sex toys and drawing up a table of sex acts they could proceed through.
"John. Look."
"What?" John looked back at Sherlock to find him taking a folded piece of paper out of his coat.
"Surely physical evidence of my love would serve better than repetition."
John unfolded the paper. It was a medical chart.
"My bloodwork, John. Heightened presence of dopamine, oxytocin, and serotonin. It's quite remarkable, my reaction to you is more potent than cocaine. Proof that I love you."
John stared at the chart, a tingling warmth spreading through his chest and threatening to burst out of his throat.
"I'm going to get this framed."
He launched himself at Sherlock, who grunted in surprise at his sudden armful of short, blond, very happy army doctor. John pushed him down on the sofa and straddled him, clutching the lapels of Sherlock's coat as he kissed him deeply.
"You're a wonder, Sherlock Holmes."
Sherlock tilted his head slightly, looking at John with a small smile. "I love you."
John grinned, popping open the buttons on Sherlock's shirt. "What happened to hating repetition?"
"I plan to repeat it under different circumstances to see your reaction. Should be fun, you're never boring. Anyway, your lesser intellect might need the reminder."
John chuckled, too pleased to be remotely offended. Sherlock ought to take his blood now. His dopamine levels were probably through the roof.
"Shut up, you idiot," he said, mouthing down Sherlock's jaw and kissing a sloppy trail down his neck.
Sherlock put both hands on John's rear and pulled him in, slotting them tightly together with their cocks pressed to each other through layers of fabric. He circled his hips, John groaned. Sherlock leaned in close and flicked his tongue across John's ear.
"I love you," he said again, his voice sultry and low like honey and scotch.
John's breath stuttered. He shoved inefficiently at Sherlock's shirt, rasping, "Clothes. Off."
Sherlock grinned in delight. They divested themselves both of their clothes, leaving a carelessly rumpled heap on the floor. Once naked, Sherlock knelt between John's legs and licked a fat stripe up John's leaking erection, mouthing at the glans, before lowering his mouth until John's cock nudged the back of his throat. He looked up at John and rumbled something unintelligible.
"Oh, god," John choked.
John had never really expected Sherlock to be good at sex before they started having it - in fact, he had wavered between thinking Sherlock was asexual or celibate. But Sherlock had learned everything John liked very quickly. Sherlock's intense gaze would be fixed on John the entire time, taking in John's every minute reaction. He enjoyed turning John insensible with pleasure more than getting off himself. John had always been an attentive and considerate lover, but in the face of Sherlock's whirlwind passion, he could barely think at all.
John could never get used to this sight, Sherlock on his knees in front of him, eyes dark with lust, lips stretched around John's cock, it was shocking and dirty and like a remarkably visual fantasy.
Saliva dribbled messily down Sherlock's chin and John's cock. Sherlock licked his lips as he pulled back, rubbing the moisture into John's cock with long, fast, strokes.
"I love your cock, John," Sherlock said, his usual baritone made rough with abuse, and John moaned, cursing under his breath, certain Sherlock was going to be the death of him. "It's so...excellent. Responsive. Yes, it jerks, like that, when I...provoke it."
Sherlock breathed over John's cock, his gaze still boring into John knowingly.
"Shall I continue?"
"God, yes. Please, Sherlock."
Sherlock dipped his head to lave John's balls with short, wet licks, his fist closing around the base of John's cock to hold it quite firmly. John's hips began to thrust of its own volition, and he began attempting to fit his own fist into his mouth to prevent himself from begging more embarrassingly.
"Stop that," Sherlock snapped. "We've still got those handcuffs, you know."
Whimpering, John grabbed at Sherlock's curls instead, containing the urge to shove Sherlock's face into his crotch. He shifted his legs wider apart and let the small sounds spill from his mouth as Sherlock resumed his attention to John's much-loved appendage. John barely noticed when he began thrusting his cock into Sherlock's mouth in short, fast thrusts, but, at a protesting noise from Sherlock, remembered to stop tugging Sherlock's hair. Instead he clutched the sofa cushion with such force as was possibly detrimental to the cushion's longevity, feeling the sparks of his arousal build until it was red hot and pulsing. Just then, Sherlock shoved a finger into his arse, and John was so surprised he could only choke out a very strangled version of Sherlock's name as he came into Sherlock's mouth.
"Jesus Christ," said John weakly, when he found his words again, "That was new."
"That was excellent," Sherlock purred, pleased as a cat, maneuvering John's pliant and sated body until he was lying on the sofa and Sherlock's very hard cock was poking John's thigh. "May I, John?"
"Hn?" John shifted, reaching for Sherlock's cock, but with a gentle thrust Sherlock had fitted it against his arse, rubbing against John's hole.
"Can I fuck you?"
John's heart rate picked up again. That. Would definitely be new.
Sherlock leaned closer, his fringe tickling John's brow. "Please, love."
John melted, tugging Sherlock's head down for a messy kiss. Sherlock gripped John's hip and thrust, exhaling a shuddering breath across John's lips as his cock dragged across John's sweat-dampened cleft.
"Lube," John muttered.
"Yes, that," Sherlock agreed distractedly, throwing his front off the sofa at a precarious angle and digging around under it until he lifted himself back up with a thin tube in his fingers.
"How?" John began, and huffed an amused giggle. "I don't even care."
"Very wise," Sherlock said, squeezing entirely too much lube onto his fingers.
John lifted his hips to allow Sherlock easier access, nerves thrumming through the end of his post-orgasmic contentment.
"Is there a condom under the sofa as well?"
Sherlock pressed two fingers into him at once, slow and slick, twisting his wrist in short, sweeping motions as he worked them in deeper.
"No, don't need one," he said, his eyes fixed on John's hole.
"But-"
"No, we're clean, I don't care about the mess, I'll lick my semen out of you if you object to getting rid of it yourself."
John's breath left him in a rush and didn't come back.
Grinning widely, Sherlock scissored his fingers inside John and stroked until he found John's prostate.
"Mgh!" A startled sound was pulled from John's throat.
"Oh, that was a lovely noise," said Sherlock, smirking. "Let's have it again."
John's eyes rolled back with the effort of keeping the noise in. Looking pleased with himself, Sherlock squeezed a third finger into John's body, pumping a few times before inquiring, "Do you reckon that's enough preparation?"
"I reckon you should hurry the fuck up."
Sherlock withdrew his fingers, wiped them on his cock, and added more lube. There was a lull as John stared at him, chewing his lip, watching Sherlock palm his glistening cock before suddenly tightening his fingers at the base of his cock, panting, his eyes snapped shut.
"Thinking about your grandma?" John quipped.
"Shut up, John!"
"Diseased liver," John said helpfully. "Mycroft wearing knickers."
"You're not helping!" Sherlock opened his eyes to glare, his voice tight with suppressed laughter.
"I'm not?" John made an outraged face. "Does that turn you on, then?"
"You're putting me off altogether," Sherlock retorted, obviously lying, as he pushed his cock against John's loosened anus.
John hissed, hooking his arms around Sherlock's neck and his legs round Sherlock's waist until he was wrapped around him like an octopus.
"Relax. It'll only hurt a little, doctor."
While John shook with laughter, Sherlock thrust all the way in.
"Ow, you fucker," John grunted, drawing in deep breaths against the burning, throbbing fullness in his arse.
"Doctors always lie," Sherlock said, his voice too low and tense for the banter.
John looked at him. Sherlock loomed over him, one hand planted on the sofa cushion by John's head, his pupils so dilated his eyes were black, his mouth pressed into a thin line, his breath coming heavily through his nose. John shifted slightly, and Sherlock made a deep, nasal sound, his nostrils flaring.
"Are you okay?" John asked.
Sherlock swallowed. "I predict this will be a rather short intercourse, John."
John's lip twitched. "Should I talk more about Mycroft?"
"Talk decidedly less," Sherlock snarled.
John sighed as Sherlock began to move his hips, grinding against him in gentle circles that sent trickles of arousal to John's spent dick.
"Bit more," John prompted, and Sherlock let his thrusts become a little more pronounced, drawing back an inch or two before plunging back in. "God, that's good. The things I did not know. I should have taken up James on his offer back in the army."
"You're thinking about your ex while I'm inside you?" Sherlock drew back and slammed back in in retaliation, drawing a loud groan from John.
"Yep. Sorry. Sherlock. V-very bad manners of me. Oh, my god. I love you-Sherlock, please!"
Sherlock's mouth covered John's as his thrusts sped up, kissing clumsily with their mouths open and groans spilling into each other. Sherlock's hands found John's hips and held him firmly in place as he fucked into him, slick, slapping sounds filling their ears until he finally thrust into John so hard they both banged into the arm of the sofa. He collapsed heavily on top of John and released his hips, slowing into lazy, shallow thrusts that eventually ended with them wrapped entirely around each other, sticky and sated.
"I love you, John," said Sherlock, tilting his head to press a kiss to John's forehead.
John grinned, sore and exhausted, half-hard but with no intention to do anything about it, and so filled with affection that even with Sherlock on him and around him and in him, he wished that he could have still more.
"Considering the evidence, I'm pretty convinced."