John held the little bundle as they walked up to the door of 221B.
"Are you sure you don't want me to be there? What if she needs—"
"It will be fine Mary. You know how Sherlock is. Better if I go alone." He whispered.
The door opened and the couple found Sherlock sitting on the couch, a little too casually.
"Hello." Mary greeted with a kind smile.
"Ah, hello." The detective said, eyeing John as he sat up.
"You do still want to meet little Sarah? You said you wouldn't until she was more…sturdy." John said with a little glance at his wife.
"In another few years. When it's not squirming or drooling or having any other bodily actions it can't seem to handle."
"Right. Well you'll have no such luck." John stated, shifting the now visible baby girl in his arms.
There was a bit of an awkward silence when John didn't seem to move from his place at the door and Sherlock diverted his eyes elsewhere, before Mary cut in, "Well then, I will see you later." She kissed her husband's cheek, then the top of Sarah's blonde head. "Bye." She smiled, before walking back down the stairs.
Sherlock stared at the little baby covered in a pink embroidered blanket and matching onesy and pants as John finally joined him on the couch and turned her toward Sherlock, big, almost familiar pale blue eyes staring up at him.
"Say hello to your uncle Sherlock Sarah," John said happily, waving her little hand at Sherlock.
"Really John," He said flatly.
"The voice, is it really necessary?"
John straightened, "All parents talk to their kids like that."
Sherlock stated, "They don't actually."
"And see how you turned out?"
The detective gave his old flat mate a sarcastic smile.
"Come on Sherlock, we've been by several times and you've barely even acknowledged she exists, don't be a baby and just hold her will you?"
When Sherlock made no move to do as he asked, John lifted the yearling from his lap and set her onto Sherlock's knee. The detective's nerves went on alert and was forced to take hold of her as John let go.
She was so small and moving constantly and smiling and just staring at him.
"See?" John said as he watched the two. "She likes you."
"Can't see why." Sherlock stated flatly as Sarah grabbed his finger with her little fist.
"The world is a mystery." John said with a small smile.
She studied Sherlock's index finger with curious joy and pulled it toward her mouth.
Sherlock quickly resisted, "John, John what is she doing?" He held firm when little Sarah began to give gurgled spurts of protest.
"She's teething Sherlock."
"My finger is not a chew toy." He replied sharply.
"She won't bite."
Sherlock looked away from the baby and glared at his friend, "That is not the point John. It has germs and saliva and is highly unnecessary."
"She is not an it and you are being dramatic."
Sherlock made a sound of disgust as he realized he'd let his guard down and the said appendage was now being gummed.
John laughed at the look of mixed repulsion and surprise on his friend's face which in turn made Sarah turn to her father and giggle.
"There. You've had your fun, made your point. You can have her back." Sherlock said, attempting to hand back the child.
John ignored him however with a slap to his knees, "I'll go make us some tea."
Sherlock and Sarah both watched him go.
When John was out of sight however, her face turned into a frown and small cries at his absence.
"See, she's crying!" Sherlock called to the kitchen.
"She's about ready for a nap!" John answered un-phased. "Just talk to her and bounce her a bit on your knee!"
He looked down at her again, testing the given instructions unsurely. "This is absurd," Sherlock grumbled.
Sarah looked up at him, still wearing a frown and sobbing.
"I don't see why he insists on making a point, whatever it is. Suppose he thinks he's being funny," he added, still bouncing her on his knee. "I don't see how you could enjoy this jostling, or how it could possibly make you quiet."
Seeing her previous content coming back, he continued on with a softer tone. "I never imagined John being a father. I can't see why anyone would want to. Suppose it's essential to life."
He paused when she kept staring at him with those big glossy eyes that were so much like her father's. "You're a defense mechanism you know. Babies are visually appealing so predators will not eat them. Can't see what good that does."
He stopped the bouncing and waited for the crying to ensue. When it didn't and she instead leaned her tiny form on him, examining his fingers with drooped eyes, he hummed, "But nothing will ever happen to you. Because you've got the best you could get in John. And we will never let anything get to you."
(A/N: This was fun to write, uncle Sherlock with John and Mary's kid :D and incase anyone's wondering at the choice of Sarah for the girl's name, it kinda just stuck.)