A little idea I got off of Tumblr, hope you like!
"John, JOHN!"
Sherlock sprinted up the stairs into their shared flat, yelling for his flat mate. He skidded to a halt just inside the sitting room, blinking in confusion at a familiar woman. Molly Hooper, Specialist Registrar at Bart's, was curled up in John's armchair, her wet hair piled up in a bun on top of her head as she nursed a cup of tea. Sherlock's eyes widened as he took in her state of dress, or rather, undress. Molly was wrapped in John's dressing gown, with a towel around her shoulders, looking for all the world like she'd just climbed out of the shower. Sherlock's mouth opened and closed a couple of times as Molly scurried out of the chair and stood blushing in front of him. He valiantly tried to keep his eyes from where the neck of the gown had opened slightly due to her movements, exposing enough skin for him to assume that she was mostly, if not completely, naked underneath the silky material.
He cleared his throat.
"Molly," Sherlock licked his lips, registering his quickened breathing. He'd always been attracted to the petite woman, but had put aside any sentiment for her, telling himself that the work was enough, that it was all that mattered. Now he walked into his flat to find her naked in his flat mate's dressing gown.
Said flat mate sauntered into the room at that moment, clad in pajama bottoms and a tee shirt, yawning. Sherlock wondered exactly how late it was. He knew it was dark outside but he'd lost track of time while out working on his most recent case. And while he was working, his flat mate had apparently been busy stealing HIS pathologist. In an instant Sherlock was furious.
"Doctor Hooper," he said coldly, flicking his gaze over her. He skipped over the favorable things he saw, like how soft the skin of her bare legs looked, how sweet her freshly showered scent was, how beautiful her wide brown eyes looked in her makeup free face.
"I thought I told you to avoid relationships in the future. I doubt 'three-continents Watson' will be settling down at any point in the near future.
Molly gaped at him, hurt and embarrassment coloring her cheeks and John gave a loud, long-suffering sigh.
"Sherlock," he began, "this isn't what it looks like."
"Whatever do you mean, John? You just flatly refused to 'skip work'," Sherlock made sarcastic air quotes, "to help me with a brilliant case and then I come back to find you and MY pathologist in varying states of undress lounging about the flat! What exactly did I miss?!" By the end of his tirade he was shouting and gesturing wildly as Molly and John looked on, both speechless.
John glanced over to the little woman, and shook his head.
"Molly, he's all yours. I'm going to bed." He walked over and gave her a one armed hug before heading towards his room. When got to Sherlock, he clapped one hand on his shoulder and chuckled.
"You've got some explaining to do, mate."
Sherlock's brow furrowed in confusion. "I'VE got some explaining to do?" he repeated incredulously.
John merely chuckled again and continued on his way to his room. "Good luck," he called over his shoulder, and Sherlock wondered if it was directed at himself or the small woman in front of him with her hands on her hips. He had a feeling it was meant for him.
"Sherlock, you always," she broke off and shook her head. "No I've already told you that." She gathered the dressing gown around her, obviously steeling herself against his cruel jabs. "I was caught in the rain earlier when I was bringing the liver and fingers you demanded, requested," she corrected herself almost automatically. "Anyway, I was soaked through and John had just gotten in as well so he offered to have Mrs. Hudson dry my clothes and gave me his dressing gown to wear until I could go home."
Sherlock mentally kicked himself for jumping to conclusions. There was always something he missed and he had completely forgotten that he'd asked Molly to bring the body parts to his flat that night. He could have easily gone to get them but he'd wanted to see her outside of work, hoping she'd leave her hair down, something he loved to see.
"I, uhm," he cleared his throat, unused to apologizing but feeling that he needed to. "I'm sorry, Molly Hooper."
Sherlock stepped closer to her and ducked his head to press a light kiss to her cheek.
"Not good enough, Sherlock," came John's cheery voice from behind the detective. Molly flushed scarlet and Sherlock growled low in his throat, turning his head to see his flat mate wander through the room into the kitchen.
"Thought you were going to bed?" Sherlock ground out, his patience low.
"Was. I got thirsty." John raised his glass of water in a toast and grinned mischievously. "You know Sherlock, I could have sworn that you called her 'My Pathologist.' That couldn't be right, though, huh Sherlock? I must be hearing things. After all, you're married to your work and Molly's a free woman," John trailed off as Sherlock sent him a furious glare.
"Actually John, Molly and I are embarking on a romantic relationship."
"We are?"
"You are?"
Molly and John spoke at the same time, both staring at Sherlock as if he'd grown a second head. He rolled his eyes.
"Molly, you are attracted to me, are you not?"
She blushed and stammered something intelligible, which Sherlock took as a yes.
"And you would be open to a committed romantic relationship with me?"
She just stared at him with her mouth open before glancing at an equally dumbfounded John.
"Uhm, yes I suppose so," she finally replied and Sherlock grinned triumphantly.
"There, so now John, she is in fact MY pathologist. Now piss off, so I can shag her into the mattress."
John choked on his water.