A/N: Yes, I'm a bad girl for writing this, but I just got obsessed with the idea and had to get it down. We need all the good times we can get after seeing Endgame, right? ;)

"Stop lying!"

The words came out in a hiss, accompanied with a harsh shake and Natasha couldn't stop the little moan that escaped from her throat.

Her eyes flashed and she cocked her head to the side, challenging him. "Or what?"

In her previous line of work, she was used to being in uncomfortable situations where she had to dominate and, on occasion, be dominated by her target, but her thoughts had turned down a pleasantly dirty path this time. Steve wasn't a target and a SHIELD hospital was hardly the place, but she wondered what it'd be like if he fucked her in this room. The door was half open where anyone could walk past and see them. It was a titillating prospect.

Steve saw the fire in her eyes and knit his brows together. He lowered his gaze to her mouth which was now blowing out deep, panting breaths and he took in the erratic pulse in her neck. Now he stepped back, the anger seeming to ebb away as he realised she was aroused.

Natasha pulled him to her, stood on her toes and pushed her lips against his. It wasn't tender, rather a frenzied, passionate kiss. She'd dreamed about doing this ever since she met him on the helicarrier two years ago and who could blame her? The man was fine as fuck. Not to mention that he was a great leader, he also had the greatest ass she'd ever seen on a man.

Many times, she thought about just grabbing him and squeezing him, but she had too much respect for Steve as her partner and her friend to touch him like that. If she were going to do that him, it would have to be consensual - so she didn't get in trouble with HR - and for his sake so he wouldn't be angry at her for violating an important boundary in their friendship.

He'd been so angry at her when he slammed her into the wall, which was a first and Natasha knew Steve had probably never done anything like that to a woman in his entire life. He did grow up in the thirties. Hell, he probably had never made out with anyone either, so who knew what had been going on inside of his head?

When he actually began to respond to the kiss, Nat smirked and rested her hands at his sides. Perhaps America's golden boy wouldn't be afraid to open himself up to the joys of the flesh.

After counting to ten, she slyly pushed her tongue to his upper lip and subsequently, he gave her entrance. She wasted no time in massaging his tongue with her own and felt a surge of giddiness as he returned her affections.

Mm, he tastes like plums. Must have had a quick snack for lunch. I know I tease him about eating so many fruits and vegetables, but I'm glad he's such a healthy eater. This would have gone south pretty fast if he'd eaten spaghetti.

Speaking of south, Steve's hands had begun sliding down Natasha's shirt, pausing to squeeze her clothed breasts, a delicate action that caused her to moan in pleasure. She loved it when a man squeezed her like that, but Steve was so gentle, his touch sensual and thorough. It was as if he thought she were something special, something to be cherished and the feeling made her a bit dizzy.

She didn't have time to dwell on what those feelings meant because Steve started tugging her skinny jeans down her legs. As he worked on her jeans, she did the same with his sweatpants. They were small and she figured he'd stolen them from the locker of an employee who worked here. Who knew Captain America would be committing petty crimes in this day and age? If they weren't in danger of being caught, she'd have laughed. In moments, their bottom halves were bared and all she could do was hold her breath in anticipation as he looked at her.

They were friends, good friends, and now, they stood on the precipice of jumping into something deeper and potentially dangerous. If they did this, things would never be the same between them again.

Natasha knew that, for Steve, hit it and quit it was not his thing. He was the kind of man who'd be steadfast and true to her, no matter what. She'd seen the way he would look at her when he thought she wasn't looking, the stiffness in his posture whenever another man flirted with her. She knew he was interested. As for her? She'd been falling for him little by little every day. The more time she spent with him, the more Natasha knew that she couldn't have chosen a better man.

When he showed the first sign of hesitance since that first kiss, Natasha took his hand and pressed it to her center. She was already wet and she wanted him to feel, to know that she was ready for whatever came next. This was a step they'd never taken before, but she was willing to do this because she believed he was worth it. And she was tired of denying herself the joy of being with Steve.

He explored her insides with two fingers, probing her inner walls and listening to her halted breaths when he'd touch her in certain spots. Their eyes were locked on to each other, making the moment even more erotic. Steve's gaze was so hot it could have set her on fire and she would've thanked him for it. Natasha began bucking her hips, urging his fingers further.

Steve stroked her with her juices like an artist with a paintbrush and she clenched her thighs tightly. His shaft stood at attention and poked her in the stomach which made a light giggle slip from her mouth.

He raised an eyebrow. "Something funny, Romanoff?" Each word he spoke was enunciated with a slightly harder thrust of his fingers and she gasped at the force of it.

"No, mmm. I'm just admiring what a lovely cock you have. It's like something out of a painting." She cupped him and he hissed, obviously not expecting her to touch him. His reaction encouraged her and while he stroked her depths, she ran her hand up and down his length, pumping him.

Steve's fingers went higher into her heat until he came in contact with her clit. He rubbed the fleshy button, enjoying the shudder of his lover's body when he touched her.

Beads of sweat formed on Natasha's brow and she brushed her lips to Steve's again. It was beautiful, hearing his strangled moans because of what she was doing to him, but it wasn't enough. She needed more and she wasn't sure how much longer she could hold back her orgasm.

With all her strength, she removed her palm and looked at his face.

"Take me, Steve. Please."

Her request moved him to take action and he smoothed his fingers on her clit once more before removing his hand from her completely. Steve licked his fingers, giving her a half smile and she gaped at him. She never knew he could be so naughty! When he finished lapping the moisture from his fingers, he wiped his hand on his shirt, cupped her ass to hold her up, positioned his body and pushed. Inch by inch, he delved into her entrance, taking his time to feel as much of her as he could.

Natasha sucked in her bottom lip and closed her eyes, welcoming him in unadulterated eagerness. Her walls were dripping at this point - they had been wet since the moment he slammed her into the wall - which gave him easy access to her warmth. Their lips collided again, stifling the moans emanating from them both.

He entered her slowly, but once he was fully inside, he began to pick up speed, pushing her legs so they wrapped around him. The change in position forced him deeper and she closed her eyes. On and on, they pushed against each other, thrusting hard and fast. Natasha bucked her hips to meet Steve's and he grabbed her hand, clasping it and holding it to the wall. Her nails dug into his skin and the pain just increased the pleasure of their sex.

"Ah, you're so tight...!"

His words spurred her on and made her smile wickedly. She'd been without a partner for a few years, so the only time she got a good orgasm was when she masturbated. And yes, she imagined Steve while she fingered herself. How could she not? He was a man of great strength and vitality and he'd been part of her fantasies for years.

But this was a million times much better. There was nothing quite like the sensation of a handsome man filling you with his need and Steve was very well-endowed. He managed to get deeper than she imagined and literal stars were in her eyes as he fucked her. The man was so damn good at this that it was odd to think he had been a virgin beforehand! Perhaps she was the lucky woman who managed to bring out this virile, passionate side of him.

"Nat, unh, that feels so good..."

Spurred on by his murmurs of arousal, she gyrated against him. Being a professional dancer gave her a special skill when it came to knowing just how to move her body and when to touch a man in all the right places. In addition, her fingers travelled under his shirt, splaying out on the flat expanse of his stomach. The movement caused her walls to clamp down harder with a quicker speed.

Steve's lips parted in an O and he felt his heart pound. The way her petals grabbed hold of him, the rhythmic response of her body matching the thrusts of his pelvis, it had his eyes rolling in the back of his head. Natasha had never been this hot before in her life.

She was so, so close. Steve's fingers were deep inside her core and her eyes rolled in the back of her head when she heard squelching. He was hitting every area inside of her, pounding her with a ferocity she'd never experienced. Her walls fluttered and she felt her juices leaking down her thighs.

"Steve, I'm-I'm gonna-"

"Come for me."

It was too much. His husky voice, his shaft pulsing inside of her center, the fact that they could be caught at any moment. These were all the final factors that made her hit her climax. Natasha's legs shook and she wrapped her arms around him. Steve reached his own completion seconds after she did and buried his face in her neck to cover his moans. He overstimulated them both by pushing into her one, two, three more times until he was sure he emptied every last drop.

Natasha slumped in Steve's arms and he held her close, bracing her to the wall so neither of them would collapse. They were thrown by the post-climax haze that enveloped them. She'd never had a sexual encounter as intense as this, nor was she likely to again unless it was with him.

When they felt strength return to their limbs, they adjusted their clothing as quickly as possible. Now that they finished, their senses were at high alert. Keeping that in mind, Natasha tugged Steve to her and kissed him soundly before leaning back to the wall. He watched her carefully, curious of what she was about to say.

"So...was this a one-time thing or do you want to exchange phone numbers?" Her words were a light hearted tease, of course.

Steve chuckled and put his arm around her waist, slanting his mouth over hers for a brief smooch. They separated and he nuzzled her nose, blue eyes shining with adoration.

"You know I could never have a one night stand with you, Nat. You and me, we feel right and this isn't the best time to discuss it, but after we figure everything out with SHIELD and this assassin, we'll set up a date."

"Oh? Are you planning to wine and dine me, Steve?"

"Yes, but I plan to do a lot more to you than just that." His eyes burned as he looked at her.

Natasha could already tell that this man was going to spoil her and she knew she'd enjoy every minute of it.

"I like the sound of that, soldier."