When Carol thought about it later, she thought maybe Captain America was looking to let go with someone who he wouldn't break. She had no idea why she said yes. It all seemed to happen to naturally. After they'd finished at the museum she'd offered to fly him home. He'd invited her to use his shower. Then there was sweat and soap and big hands pressing her up against wet tiles and the knowledge that she could squeeze her thighs as tight as she liked and he'd just keep on thrusting.
When she was dressed in a fresh uniform he argued with her about her name then left to talk to the President. Same old Steve. It wasn't what she'd been expecting.
She let her thoughts roam as she flew to Tracy's – from Tracy herself, to Helen, then back to Steve. It wasn't like she hadn't done that sort of thing before; the adrenalin of battle was always easiest to drain away with some meaningless sex, but she wouldn't have thought Captain America was the type to go for that.
It happened at odd times after that. When they got back from destroying Doombots. After Cap had to take out a dead president.
After they'd taken down Han she started to worry. Steve jumped out of a plane and she managed to grab him. When she asked how he knew she'd catch him, he just said, "I know you," with that quiet sincerity he had.
Was this more than she thought it was?
Then Loki hit and somehow part of the tower was gone and it was Carol inviting Steve to use her shower, since his was no longer there. They ended up in her bed, covered in bandages and starting to giggle when each touch brought a slight wince and a need to move to a stretch of uninjured skin.
"I feel like Indiana Jones," she said.
Steve pointed to his forehead. "It's not sore here."
She leaned forward, his cock moving inside her as she kissed an unbruised spot on his brow. "Where else?"
She was grinning as she pressed her lips to his cheek, to the corner of his mouth avoiding his cut lip, the inside of his bicep.
"Most of this arm," he said, motioning to the forearm that was protected by his shield. She licked a stripe from wrist to elbow and felt him twitch inside her. She rolled her hips, the shock of pleasure overriding the twinge in her knee.
"I didn't fall on my ass," she told him and if there was something Captain America did well, it was obey the orders he liked with alacrity.
"Yes, Sir," he said as his big fingers dug into her buttocks.
"You can call me Colonel."
That brought a stuttering laugh and a hard thrust of his hips and she lost her balance, falling heavily onto his chest. They both let out a hiss of pain.
"You know, we'll both be healed by morning."
"Not nearly as much fun, Captain."
He nodded and pulled her closer, then twisted his hips so she was on her back, his handsome face looming over her, their chests pressed tight.
"Permission to move, Colonel."
"Granted, soldier." She added a nudge with her feet and a thrust of her hips and boy could he take orders because he put his back into it. She arched up to meet him, finally letting the need to move free. It didn't take either of them long after that, the impressions of her fingers on his shoulders just one more set of bruises that would heal by morning.
The stress of the multi-day battle finally seeped out of her and Carol fell into a deep sleep.
Sometime around dawn she woke, the habit too ingrained to allow her to sleep in. Steve was still snoring softly next to her, bruises gone and one arm flung up to cover his face. She slipped from her bed, expecting him to wake and grateful that he didn't.
She only took the time to pull on jeans and a t-shirt before she leaped from the balcony and into the sky. Her thoughts crowded in on her at first, the worry about Steve Rogers in her bed and wondering if she'd led him on or something. It was Captain America - did he even know how fuck-buddies worked?
Then the feel of air rushing past her body did its trick. Yeah, being in a cockpit was amazing, but being able to fly under her own power? Just shooting up and feeling the clouds beneath her fingers, touching the edge of space? It was the most amazing feeling in the world and it never failed to bring her back to calm. Bring her back to her center.
She hovered for a long moment at the outer limits of the atmosphere looking up towards the moon. The temptation was there to reach a hand out and fly towards it; sit and look down at the Earth looking small and fragile. Instead she turned to fly home and talk to the man she'd left asleep in her bed.
Steve was awake when she got back, standing in the kitchen chopping up kale for breakfast. She watched him from the door before finally walking in and finding coffee. Even when the rest of the team had found somewhere less like a construction site to sleep and it was just the two of them, the coffee machine still turned itself on in time for a morning espresso.
"What are we doing?" she asked Steve when she'd drained the cup.
"Well, I'm making a healthy breakfast and you appear to be fidgeting. That'd be the espresso's fault."
"That's not what I meant. I meant –"
Steve threw the kale in the blender and switched it on and Carol waited rather impatiently for the smoothie to finish mixing. She opened her mouth as soon as the machine turned off, but Steve got there first.
"Thank you for letting me stay last night when I had nowhere else to go," he murmured, not looking up from the glass he was pouring smoothie into.
"You're welcome. Steve –"
"Look. I'm in a long-term relationship with my shield." He finally looked up, a rueful smile on his face. "Or SHIELD, you know, whichever. And you've been having a succession of torrid love affairs since I met you."
She felt her eyes widening and opened her mouth to protest, but he continued.
"I think it's with the quinjet at the moment. Or there was a T6 you flew above 37,000 feet. Or –"
She felt her mouth starting to break into a smile. "It's not a series of affairs, Captain. One long affair with the wide-blue sky; we just invite in other partners occasionally."
"I've heard of these 'open relationships'." He even made air quotes. "There was a diversity seminar that said I have to be supportive of all forms of love."
"Well, I appreciate the support."
"Is it open enough to include me on occasion? At mutually agreeable times in a way that will only include sleeping in the same bed when one of the parties' sleeping quarters has been destroyed?"
"It's probably that open. And if things change?"
He handed her a glass and, when she stepped forward to take it, snagged her belt loop and pulled her towards him.
"If things change we renegotiate. But at the moment we have the whole tower to ourselves and this is the best chance to – what do they call it? Christen? – the kitchen without interruption."
She took a long swallow of the smoothie while she looked at him. "I'll get kale on my butt."
He gave half a shrug. "Not if I'm on the bottom."
He hopped up onto the counter and she stood between his legs to undo his jeans. "We've known each other for a long time, and I have to say this sort of attitude was not what I expected from Captain America."
"You know me, Captain Marvel." He lifted her easily onto his lap. "I'm all about being open."