Natasha doesn't like nicknames until Steve is the one giving her them. 

AKA the other Avengers get upset because they can't call her Nat and Steve can.

"Hey Tasha-" Clint started, quickly being interrupted by a glare from the red head. 

"Natasha." She reminded him. 

Clint rolled his eyes, "Whatever, Natasha, I was going to invite you to lunch with Laura and I but I'm not sure I want you there anymore. What kind of friend doesn't let her other friends give her a nickname?" 

Natasha glared at him, "The kind that doesn't like nicknames. And thanks for the offer but I'm on my way to help Steve train some of the lower level agents." 

Clint raised an eyebrow, "How did you get stuck doing that?" 

Natasha frowned, "That's part of my job."

"Well obviously, but you always find your way out of doing stuff like that," Clint pointed out as though it was obvious. 

Natasha shrugged, he wasn't wrong but she wasn't about to tell him that she had agreed to it because Steve had asked for her help specifically and she really couldn't tell him no. Especially not when he looked as lost as he normally did when asking for her help with something. 

Clint rolled his eyes again, "Fine. Keep your secrets. Maybe tomorrow. See you later Natalia." 

Natasha jabbed him in the ribs with her elbow, "I swear I'll kill you without regretting it Barton." 

He raised his hands in mock surrender, "Okay. Okay. Sorry. Natasha it is."

Natasha sighed and walked off to the training room. 

"Agent Romanoff, Director Fury is asking for you. He says it's urgent," One of the agents Natasha hardly knew said to her. 

Natasha frowned but nodded, "Okay thank you." 

She walked towards Fury's office and pulled out her phone as she walked, pulling up Steve's contact. 

Got called into Fury's office. I may be a few minutes late to training. She sent, hoping that whatever he needed her for was something small. 

Steve replied in a matter of seconds, No problem. I'll get them started while we wait for you.  

Natasha sent him a thumbs up emoji and walked into Fury's office. 

"I heard you wanted to see me." She said the second she walked in. 

Nick looked up at her with a raised eyebrow, "Yes. We need you to go on a mission today. It shouldn't be long and your main role is going to be supervising some of the younger agents but I need you ready to go in an hour. Hill will brief you on the quinjet." 

Natasha sighed but nodded, "Yes sir." 

She turned and walked out of the office and headed for the training room. She would at least let Steve know in person that she couldn't help him out today.

The young agents were already doing the two mile warmup by the time she arrived. Steve saw her right away and smiled at her, "Hey. What did Fury want?" 

"He needs me to go on a mission today. I'm due at the quinjet in an hour."

Steve frowned, "How long will you be gone?" 

"He didn't say. Said it wouldn't be long though. You think you can manage training them alone today?" 

Steve nodded, "Sure. It won't be quite as fun though." 

Natasha smirked, "I'm sure they will all be thrilled that I have to miss today's session. Make them run a few extra laps at the end for me?" 

Steve laughed, "Alright. I'm telling them it's under your instruction though." 

"Good. Then when I get back they'll know exactly what kind of training they can expect."

Steve smiled, "You're brutal." 

"That's why I'm the best," Natasha said, grinning.

Steve rolled his eyes, "Whatever you say, and be careful today okay. I'd be awfully bored around here without you to help me torture recruits." 

Natasha smiled. "Will do Cap. See you later." 

"Bye Nat," He said with a smile, and for once, Natasha didn't have the instant urge to remind him that her name was Natasha. She'd do it next time but right now, she had to get ready for her mission.

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Natasha's mission really had been a short one. She had been gone hardly a day and finished debriefing and paperwork by the end of the second day. 

She had been walking back to her room when she caught sight of the others watching a movie in the living room.

"What's this all about?" Natasha said, coming up behind the couch and making all of them flinch in surprise. 

"Oh. Hey Natasha. We didn't know when you'd be back but Cap saved a seat for you just in case," Tony said. 

Natasha raised an eyebrow but came around the couch to sit down between Steve and the arm rest. There wasn't much space which meant that she and Steve were very close. Not that she minded of course...

"What movie is this?" Natasha asked Steve. 

"Um, I don't know. Something Space wars?" 

Natasha grinned, biting back a laugh, "Star wars?" 

Steve nodded, "Yeah. That's the one. It's very confusing." 

Natasha shrugged, "It's not so bad if you actually pay attention." 

Tony threw a piece of popcorn at her, "There's a movie on Nat, stop talking." 

Natasha threw a coaster sitting on the table besides her at him, "Don't call me that." 

Tony frowned and rubbed the spot on his head where the coaster had struck me, "Ow! Why can't I call you  Nat? It's a nickname. Do you prefer Natalie, or Red, or maybe -" 

Natasha grabbed a remote and cut him off by throwing it at him with deadly precision. He ducked out of the way with a loud yelp and glared at her.

"You're insane." 

Natasha shrugged and relaxed back into the couch to finish watching the movie.

Steve asked her probably a million questions throughout it but she couldn't say that she minded too much. His cluelessness was pretty endearing. 

Once the movie was finally over, Natasha was the first to stand up, followed by Steve. 

Everyone began to filter out of the living room and because Steve and Natasha lived on the same floor, they took the elevator up together. 

"So what's with the aversion to nicknames?" Steve asked. 

Natasha shrugged, "I don't know. But I know I don't want Tony calling me Nat." 

"Clint?" 

Natasha shook her head, "Never. The other day he called me Tasha and I almost tased him." 

Steve laughed, "I guess I should stop calling you Nat then?" 

Natasha paused. When Steve said it, she actually found that she loved the nickname, "Actually, I don't mind so much when you say it." 

Steve raised an eyebrow, "Yeah?" 

Natasha nodded with a small smirk, "Plus, I know it can be hard to remember things in your old age so if the only part of my name you can remember is Nat than I guess you can call me that." 

Steve rolled his eyes, "That was uncalled for." 

Natasha laughed and shrugged, "I'd say I'm sorry but we both know I'm not." 

Steve nodded with a laugh of his own. The elevator doors finally opened and the two exited in silence. When Natasha arrived at her door she turned back to Steve with a smile. 

"Goodnight Rogers." 

Steve smiled back, "Goodnight Nat." 

Natasha smiled at his new name for her and walked into her apartment.

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Steve had been gone on a mission for three days now and Natasha would be lying if she said that she wasn't missing him. 

His presence had become an essential part of her day and eating meals and training the recruits alone had become ridiculously boring without him. 

She was sure the recruits could tell. They had probably had some of the worst training sessions of their life and she didn't plan on letting up anytime soon. 

It only got worse when Maria let her know that Steve was missing in action. 

The news scared Natasha to death. She  had to practically be talked off a ledge when she grabbed her guns and headed directly for a quinjet. 

"Natasha there's nothing we can do right now. We don't even know what happened. We lost communication with the quinjet so it could be as simple as them losing signal. You are not authorized to do any sort of rescue effort right now." 

Natasha glared at Maria, "Yeah? Watch me?" 

Maria shook her head, "Romanoff, you can't do anything. Fury is working on getting communication with him and his team and we can't send in any recon until we know that this is something serious."

"That's bullshit. If this is something serious it'll be too late by then and you know it. You're putting him and his entire team at risk." 

Maria sighed, "I'm sorry Natasha but there's nothing we can do right now. I'll keep you updated." 

Natasha stormed off towards her floor and slammed the door shut behind her. 

She hated how afraid she suddenly felt and tried to remember what she had said to him last. Had it been a stupid old man joke or did she tell him to be careful?

She hated that she couldn't remember. 

She cursed and slammed her fist against the wall once she was inside her room. 

There were tears building up in her eyes but she refused to let them fall. She couldn't stand waiting and not knowing if he was okay. 

As much as she hated to admit the truth to herself, she would never forgive herself if Steve died not knowing how she felt about him. 

Another day went by and nothing had changed about Steve's status. His team was radio silent and they had no tracking for any of them. Natasha was pissed off and terrified that something had happened. 

Maria and Fury still wouldn't let her go out and look for him but they were sending some stealth agents to their last known location. 

Apparently, Natasha being Steve's partner made her too close to the issue and she wasn't allowed to make any rescue efforts.

"This is bullshit Nick. You know that I know Steve better than anyone. If anyone can find him, it's me," Natasha argued, her anger and frustration growing. 

Fury shook his head, "Right now, sending you in is a mistake. If something is a trap than I can't be without both of my best agents. We need to figure out what is going on and then if we haven't recovered Captain Rogers and his team then we will send you in with a new team."

"Oh for fuck's sake," Natasha mumbled, storming out of his office.

She went straight to the gym and started training and running until her muscles ached and she could no longer muster the energy to be angry. 

After mustering the strength to shower, Natasha began to walk back to her room.

"Nat, wait up," Bruce called, running up behind her. 

Natasha's jaw clenched, "Don't call me Nat. What do you need." 

Bruce blushed, "Sorry. I forgot you don't like nicknames. Director Fury wanted to see you in his office." 

Natasha nodded and walked away without another word. 

"Are you finally sending me to help find him?" Natasha asked bitterly. 

Nick looked up at her, "No. I was actually calling you to let you know that he's back." 

"What?" Natasha asked. 

"He returned about an hour ago." 

Natasha didn't stick around for another second. She nodded and walked up to the elevator.

The second that the elevator opened, she knocked on his door. 

Steve opened it almost immediately. 

Natasha pushed him inside and didn't give him a chance to speak before crashing her lips against his. 

Steve tensed for a moment, seemingly shocked, but quickly responded to the kiss with an equal amount of passion. 

"Nat? Is everything okay?" Steve asked when she finally pulled apart, still clutching onto the front of his shirt like it was a life vest. 

Natasha nodded, "I was worried about you. They wouldn't let me do anything but you guys were missing for days." 

"Our quinjet died on us in the middle of nowhere and we lost all lines of communication. I'm not convinced it was a coincidence but we ended up finding a town nearby after a few days of walking where we called SHIELD and had them send a new jet."

Natasha sighed and pulled him down for another kiss. 

Steve responded for the kiss but looked extremely confused when she pulled away. 

"Nat, not that I'm complaining...because I'm definitely not...but why are you kissing me?" He asked, looking completely clueless. 

Natasha couldn't help but smile slightly at his confusion, "Because I'm pretty sure that I'm in love with you." 

Steve smiled, "Well I'm definitely in love with you." 

Natasha laughed and wrapped her arms around his neck, "Maybe you should prove it. And while you're at it, you can make up for scaring the shit out of me." 

Steve laughed and bent down to kiss her again, pulling her with him into his bedroom.

That night, Natasha realized how much she loved Steve calling her Nat when he turned to her and whispered, "I love you more than anything Nat." 

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"Hey Nat, can you pass me a coffee mug?" Steve asked the next morning when they were all making themselves breakfast. 

Natasha nodded and handed him a black widow mug, smirking to herself as she did so.

Tony frowned, putting his phone down and glared at her, "Hang on a damn second. How come when anyone else calls you Nat, you throw things at them, but when Steve does it, you do him a favor." 

Steve smirked to himself and Natasha shrugged. 

Tony stood up, "That's not fair. That's clear favoritism." 

Clint joined in now, "Yeah. I thought I was your best friend but you threatened to stab me when I gave you a nickname." 

Natasha rolled her eyes and Clint's eyes widened, "Wait a second...are you two," He pointed between the two of them wildly, not finishing his sentence.

Natasha raised an eyebrow, "Are we what?" 

"Are you two fucking?!" Clint yelled, drawing a dramatic gasp from Tony. 

Natasha smirked and looked over at Steve, "I think it's a little more serious than fucking but that's what we did last night." 

Steve choked on his coffee and Clint and Tony both instantly left the room with a loud groan. 

Steve shook his head and came up to Natasha, placing his head on her shoulder, "That was subtle." 

Natasha grinned, "Sorry?" 

Steve laughed and kissed the top of her head, "You're going to be the death of me Nat." 

Natasha smiled again at the nickname and leaned into his touch, closing her eyes and laughing slightly when he began placing kisses along her neck. 

"Alright, lets get a room before someone walks in," She said with a laugh as she dragged Steve out of the kitchen and up to her floor. 

Hey guys, I got way carried away with this chapter lol. It was originally just going to be a short fluffy chapter and then I went too far lol. 

I hope you enjoyed it and if you did than please comment and vote!