A/N: This was intended to be a oneshot, but one of my friends got EXTREMELY excited about it, so I've decided to continue it with follow up sex bets. Feel free to put any suggestions in your comments, because I hadn't planned on continuing and so don't have a ton of ideas sparking my interest atm.

As far as time periods go, this presumably takes place maybe sometime in season 4 when everything is good again. Barry & Iris are engaged, Cisco & Cynthia have very recently gotten together ever since she decided to stay on Earth 1. The whereabouts of Wally's two potential love interests (Jesse or Linda) are MIA for the moment, just b/c I know a lot of fans love parkwest (which I'm open to), but I'd also like to stick to tv canon & my personal fav at the moment (quickwest). And how can I pass up the challenge of TWO speedsters having sex and competing that way?! (I mean, Barry w/ his girl & Wally w/ his - though Jesse's a speedster too, so... Oh man, this could get interesting. lol.) So, Wally's involvement in these sex bets is TBD. Right now it's just Cynco & Westallen. :P

Anyways, enjoy! Feedback is appreciated! :)

*Big thanks to my beta, sendtherain, for being awesome and looking this over.

*I own nothing. No copyright infringement intended.

...

Chapter 1 - Sex-Starved

Barry walked into the room and sighed heavily, his eyes glued to Iris's smooth legs propped up on the couch cushions as she scrolled her phone screen.

She was wearing an oversized sweater and her hair was swept across her right shoulder, leaving the nape of her neck open to his viewing.

It had been three days since Cisco had stalked out of his workshop in frustration, whining about how he was tired of walking in on them in compromising positions. Barry had flushed, while Iris had defiantly told Cisco he couldn't possibly be scarred this time, since not a single article of clothing had been removed.

"Your hands were places!" He'd shot back, clearly agitated.

Iris had rolled her eyes and raised an eyebrow. Barry had stayed mum. Then Cisco had issued the challenge of all challenges and Iris, ever willing to put that boy in his place for objecting to her love life with her fiancé, had instantly risen to the challenge.

"I bet you two couldn't last one day without having sex with each other."

"Maybe you forgot that we were broken up for a week and didn't fuck at all during that time."

Barry's face had lit up fire engine red at her language, his eyes widening noticeably, but Cisco remained unaffected.

"Hard to fuck when you're barely on speaking terms, let alone in the same room."

Barry had swallowed hard, worried about more than the language now. He had an instinctively bad feeling of the direction of this conversation.

Cisco and Iris stared each other down for a full minute before the tension for Barry became unbearable.

"Guys-"

"One week."

"What?" Barry's mouth went dry but neither acknowledged him.

"I bet you couldn't go one week without having sex with each other," Cisco had said. "You're…" he'd glanced briefly over at Barry, clearly annoyed, "insatiable."

Barry had no time to be crushed by Cisco's disgust because the next word that came out of Iris's mouth had shattered his very existence.

"Deal."

He'd protested immediately and had promised all matter of things to both if only they'd undo this stupid bet, but neither relented. Iris was determined to win, and Cisco gloried in the promise of a week-long reprieve from witnessing Barry & Iris sexy times.

In fact, he wanted it so badly that he frequently egged Iris on, proclaiming they wouldn't able to make it that long with the intent of making her more determined to remain celibate.

When Barry tried to seduce her that first night - which was usually remarkably easy - she refused, reminding him of the bet they'd made.

"You made," he'd retorted. "I was highly against it from the start."

"Do you have no self-control?" She'd shot back.

"None," he'd said instantly. "Not where you're concerned."

Then she'd cupped his face, and he'd thought she would cave or at the very least tie him over with a kiss. But she had denied him even that.

"Just give me this one thing, babe. We can have a sex marathon when the week is up."

He'd blinked, not even the guarantee of a sex marathon enough to quell the dread stirring in his gut.

"But we're not even at STAR Labs," he'd protested. "We're at home. Cisco won't know if we have sex at home. And it's hardly fair for him to be-"

"It's the deal we ma-"

"You made," he had corrected again.

She'd smiled serenely, which didn't make him feel better at all.

"It'll be easier not to slip up in public if we're keeping ourselves in check in private too."

"Says who?" He'd squeaked. "I'm worked up already and it's been less than twenty-four hours. You're hot as hell, Iris. There's no way I'm going to last sleeping next to you every night."

"You do make a good point," she'd said contemplatively.

He'd wanted to be relieved, but he knew she wasn't going to cave that quickly.

"Maybe you should sleep on the couch," she'd said, and gotten up to retreat into another room.

Well, Barry had been so shocked that he'd made it his goal to convince her that he wouldn't seduce her in her sleep. He had enough self-control for that. She'd smiled that unsettling smile again in response.

"I know you do, babe," she'd said. "And don't worry, you'll get through this."

It worried him that she didn't say 'we'll.' As if she had absolutely no problem not sleeping with him for seven days straight.

Today that was being put to an end.

Barry sauntered over to Iris. When he was in front of her, he said nothing, only waited for her to become aware of his presence.

"What is it?" She asked, not looking up from her phone.

"I've had enough, Iris," he said, putting as much stubborn demand as he could into his voice.

Iris's finger stilled. She lifted her head to look up at him.

"Enough of what?" She asked.

It bothered him that she seemed to not know.

"Enough of you having absolutely no problem resisting sex with me."

A coy smile started to spread across her face.

"I have been going out of my mind," he squeaked. "But you have been just fine. Just so…so…" His eyes drifted to her smooth legs that he ached to run his hands over.

And then wrap around his waist as he thrust into her.

"I wouldn't say that…" she teased, taking his hand in hers and pulling him onto the couch beside her.

She sat up so she could pull her legs back and then draped them across his lap. His hands hovered above them, afraid this was a trap. He looked to her for direction.

"Go ahead, Bear." She nodded to her limbs laying across his. "Touch."

That word alone gave him a hard on; made him shiver.

Iris smirked. "Or maybe you don't need to."

Barry closed his eyes and reverently laid his hands on her legs, then squeezed gently, caressing them with exquisite care and barely controlled need.

And then the unthinkable happened.

A quiet moan emerged from the depths of Iris's throat.

Barry's eyes flashed open, and he turned to look at her.

Her opened more slowly, but the lust was evident in them. Barry gulped.

"See," she said. "I'm suffering just as much."

Hesitantly, unsure if this was the right move, or smart by any stretch of the imagination, Barry started to lean towards her, retreating a couple times even as his hands started to move up her thighs.

Then without warning, Iris impatiently grabbed a fistful of his t-shirt and pulled him toward her until their lips collided and a second moan was released the moment his tongue came into contact with hers.

"Wh-What about the bet?" Barry asked, a century of making out later, well aware how dumb that move was but seemingly unable to stop himself.

Iris was breathing heavily as she tilted her head back to look into his eyes.

"Let's just say I've found Cisco in compromising positions multiple times with Cynthia during the past three days, and I finally got him to confess why he was so irritated about running into us."

"We were stealing his make out spots."

She grinned. "We were stealing his make out spots."

Barry was giddy with delight.

"So…does that mean…?"

Iris reached down into her pants' pocket and pulled out a twenty-dollar bill.

"That means we won the bet, baby."

He grinned. "But that wasn't-"

"I called him out on his deceptive motivation and he caved."

Barry's eyes sparkled. "I love you."

"We have to try very hard not to fuck in his workshop, but otherwise we're home free. He will not harass us in the future for any excessive PDA."

"What's the twenty for?" Barry asked. "You guys never discussed numbers."

Iris laughed.

"That's to keep us out of his workshop for the rest of the week."

"A failsafe," he concluded.

"Mhmm." She started to pull him in again.

He moaned into the kiss. His hands started to wander.

"Touch me, Barry," she begged, a hot whisper on her tongue.

He groaned and sped them upstairs to their bedroom where he revealed himself as fully erect and frantically searching for a condom.

They both came fast, a result of their short-lived celibacy. But then they made love slowly, torturously, and more than once that night.

"No more bets like this," Barry whispered against her breast where his head lay resting after their final time that night.

Iris absentmindedly played with his damp locks and pressed kisses to his skin.

"I'll try not to agree to anything sex-related," she said.

"Only if it involves absence of sex," he clarified in his I'm-almost-asleep-but-this-is-important voice. "Otherwise…"

Iris's smile spread into a wide grin. She bit her bottom lip at his thirst, and hers too.

"Agreed," she said. "Other sex bets could get interesting."

He mumbled something incoherent in agreement and tightened his hold around her waist.

"G'night, Iris."

Iris smiled tenderly, closing her eyes as well as she relaxed deeper into the pillows.

"Goodnight, baby."