Author's note:

For a long time I've wanted to write a Darcy/Steve story. It's not very long, but here it is.
This is also the first time ever I've written smut. I hope it's not too bad.
Constructive criticism is always welcome.
Not beta read, so all mistakes, etc. are my own.

Thanks for reading.

Last night

The first rays of sunlight were seeping through the gap between the curtains, tickling Darcy's nose. She stirred, then burrowed her cheek deeper into the pillow. It was too flat and the fabric of the case and sheets and felt all wrong to her. What the hell was going on? Darcy opened her eyes, only to shut them a second later. The sun was too bright. The fog in her brain cleared after a moment and she was able to get her bearings.

This was not her bed; it was not even her apartment. She was at the Tower and she wasn't alone. That also explained the strange warmth she now felt close to the right side of her body. Her bedmate was like a walking, talking radiator.

Suppressing a sigh, Darcy cracked open one eye – half expecting to be faced with Steve being wide awake. Most of the time he woke up at the ass crack of dawn, because an enhanced human being didn't need more than four to five hours sleep per night. Today seemed to be an exception and Darcy thanked the goddess of all that was good and holy that he was still asleep. Otherwise it would only be weird. You see, she never slept at his place.

She risked a glance at the other side of the bed. There he was. Sprawled on his back, a bit slack-jawed, the poster boy of American patriotism was still firmly in the land of nod. If you looked closely you could even see a faint trace of drool tinting the pillowcase a darker shade of blue.
And Darcy was enjoying the view. Some people would probably call it staring. Just for a few seconds she felt the right to be absolutely and ridiculously stupid over the picture this man presented, slumbering like he had no care in the world.
She was not his girlfriend. No sir. There had not been any dates, flowers, movies dates, or even spending a noticeable amount of time together in public. And definitely no sleepovers.

The time they spent in each other's company had been firmly restricted to the Avengers' tower, sometimes her shoebox of an apartment in Fort Greene.
Once in a blue moon they saw each other at the lab where Darcy tried to keep Jane from pulling an all-nighter the second or third time in a row. Failing to accomplish that task was normally the very reason for the elusive visitor.

Whenever Darcy was trying to make Jane eat something with more nutritional value than pop-tarts or wanted to persuade her friend to stop working for the day, time just flew by. And that meant Darcy did sometimes not manage to get to her apartment to meet Steve on time.
He never complained that Jane saw them together, but Darcy chalked that up to the fact that her favorite scientist in the world was not thinking about anything other than opening new Einstein-Rosen-Bridges to yet unknown dimensions or something. The lack of proper food and enough sleep made it even more unlikely that Jane realized that someone was in the room with them, let alone who it was.

On the few occasions Steve came to the lab he helped her to put Jane to bed. They would take the private elevator up to his floor he would order takeout for them while Darcy was using his shower. Then came the sex. Sometimes it was hard and fast, other times slow and sensual. But afterwards Darcy would always go home. Every. Single. Time.
There were lines they didn't cross. It suited her just fine. The sexcapades they got up to.
Steve with his old-timey sensibilities would probably call her his paramour if he had had to label what they had. Modern lifestyle and its vocabulary still made him anxious from time to time.
Darcy had called him her fuck-buddy once – she had just been making fun of him- and he had nearly choked on his beer. His face had been scarlet and he was so scandalized he couldn't utter a word.

A snort of laughter escaped her at the memory.

The rustle of the sheets next to her brought her back to the present.
Steve had turned on his side, his nose and lips slightly scrunched up. It looked a bit like the face he made when he was being tickled, trying hard not to laugh.
Darcy liked those moments, when he let his emotions show. Too often he put on a somewhat stoic look to hide his true feelings, even when he was agitated or bothered by something. Tony once called it his look of "Upright and Uptight Patriotism", but Darcy knew better than that. A couple of times she had seen Steve unguarded and open. When she told him about the stupid things she and Jane did, like painting Thor's finger-and toenails pink and dyeing his hair in his sleep, he had laughed himself silly. When they had watched The Lion King Steve's eyes had been suspiciously red. She had watched the mask slide in place around other people to be lifted only when Steve thought nobody could see or when they were alone.

Last night it was that exact look on Steve's face that had clued her in something was off.

When he opened the door for her, she could see it immediately. Something was wrong.

'Hey', she greeted him. 'You were gone for a long time, was the mission okay?' She kissed his cheek and toed off her shoes.
He nodded. 'Yeah, nothin' special. Just took some time to draw out the people financing the attack.' His blank expression let her know there was something he wasn't telling her. She couldn't put her finger on it, though.

Darcy wondered whether she would cross a line if she asked him what was really going on. While she was weighing the pros and cons she followed Steve from the hall into the kitchen. Suddenly Darcy was distracted by the smell of pizza and her stomach growled. Her last meal had consisted of a stale muffin for lunch. She squinted over to the kitchen counter, where two pizza boxes were waiting.

Steve cleared his throat.
'I ordered your favorite.'
'You're the best.' She beamed up at him. 'That's just what I need now.' Rubbing her neck, she continued. 'I thought about locking Jane into her bedroom, so she wouldn't go back to work. I swear, she'll be the reason the put me into the loony bin one day.'
She walked over to the counter and picked up the boxes. 'Knife and fork or fingers?'
Steve made an indignant face. 'You don't eat pizza using cutlery - that's what pasta's for.'
Darcy laughed. She had taught him this piece of wisdom.

They ate the pizza straight from the box. Darcy's Quattro Stagione was too big for her, but Steve just ate the remaining quarter as a second helping after his extra large pepperoni pizza.

He got up to throw the boxes in the trash and Darcy ambled behind him into the kitchen.
When he turned to face her, he cleared his throat.
He opened his mouth to say something. 'Listen Darcy-'

Just then, Darcy lifted her hand to the corner of his mouth where a little bit of tomato sauce clung to it. 'You got something right there.' she mumbled, her voice a bit hoarse.
Slowly, she wiped the stain away and sucked the sauce off her finger. Steve stared at her mouth, transfixed, watching as Darcy's lips closed around her digit and made a tiny smacking sound when she pulled it back out.

'Mhmm.'

The sound escaped her mouth and the next moment Steve pressed his lips to hers, pulling her roughly against him. He kissed her hungrily, nibbling on her lower lip then brushing his tongue against requesting entrance. The way he teased her made Darcy squirm. The moment she opened her mouth he slid inside. His tongue eagerly stroked hers , urging her on. Heat bloomed deep in her stomach and she sighed into his mouth.

Slowly, she slid both hands over his shoulders up his neck feeling every bone, muscle and tendon to finally plunge them into his short hair. Steve's strong arms moved to her butt, his big hands squeezing her cheeks heartily and then grabbing her thighs to lift her up. Darcy wrapped her legs around his waist without interrupting the kiss. Only when her brain screamed for air did she break away from him.

They were already halfway to the bedroom without her realizing it. Steve knew every corner of his apartment and did not even bump against anything while finding his way more or less blindly.

He pressed hot, open-mouthed kisses against Darcy's neck and kept walking. His mouth traveled from her collarbone to the hidden spot just below her ear. She tightened her the grip of her legs on him feeling his growing erection rubbing against her center. Darcy's back arched making Steve groan against her neck. She turned her head a little and bit down on his earlobe.

Steve swore. 'Damn.'

Darcy giggled, breathing heavily.

He lowered her onto the bed seeking her mouth again. Straightening his back he pulled at her jeans. He made quick work of button and zip. Darcy batted his hands away and lifted her hips. She pushed down her jeans and panties in one quick move. Steve helped her to get rid of her top and bra and leaned in to taste her breasts. Darcy heaved a breath as he began to roll one nipple between his fingers while he teased the other with the tip of his tongue. He let it pop out of his mouth and blew softly onto the wet skin. A shiver ran through Darcy's body and she felt like would explode any minute. She bucked against Steve and reached blindly for his pants. Still, she somehow managed to open them and pushed her hand inside. She palmed his dick through his briefs and gave it a small squeeze. Steve growled. Darcy pulled at the elastic waistband and shoved it down over his ass.
His erection sprang free, ready to go.

'Now.' Darcy was impatient to have him inside her.
She needn't tell him twice. Reaching between their bodies he wrapped his hand around his shaft to guide it against her slick opening. Darcy tilted her hips a bit, her breath stuttered with anticipation and with one deep stroke he was inside her. Both gasped. Bracing his left arm on the bed, Steve withdrew a bit and thrust back inside. Darcy's legs tightened around him as she started to move with him. Their hips rolled together, getting faster and faster as the pressure built. With his free hand Steve grasped Darcy's face. He captured her lips again, kissing her deeply while rocking into her.

He drove into her harder, faster. As deep as he could go. Darcy felt as if someone had lit up her whole body. She was burning from head to toe. Hotter and hotter with each of Steve's thrusts. All sensations rushed to her center with the first pulse of her orgasm. Her skin was tingling and her hands clutched at Steve's back when his pubic bone brushed against her clitoris.

Darcy exploded with an abrupt cry. Her vaginal muscles contracted, squeezing him hard. Steve's shoulders shook as Darcy rode out the waves of her orgasm. He pulled back and the snapped his hips forward one last time. His muscles turned rigid and a guttural groan left his mouth as he came, pulsing hot inside her. He dropped his head forward, burying his face in Darcy's hair. All strength left his body and he collapsed on top of Darcy, embedded deep inside her.

He was still wearing his shoes and his pants were and uncomfortably bunched around his ankles.
'Fuck.'