"Mm, yeah, right there! Oh, yeah, harder. Harder! Yes!" The blonde threw her head back against the concrete wall, her legs wrapped around the dark-haired man's waist. In response to his lover's pleas, the man increased his pace, his large hands gripping her hips tightly as he slammed into her, to her clear delight.

"Imma make you come so hard, baby," he grunted.

"Oh yeah, make me come, yeah, yeah!" she chanted, her voice increasing in volume.

Shaking his head, Four fast forwarded the video until the couple finally finished and straightened themselves up, walking together out of the frame of the security camera. The corner of The Pit where the couple chose for their assignation was the same place Eric used to meet his Erudite handlers. So when Dauntless returned to their home, Gus' first order of business was to reposition the cameras so that there were fewer spots where people could clandestinely meet with other factions. As a result, the cameras were picking up more instances of illicit sex than Four had ever seen. "I swear, this faction is obsessed with sex," he muttered to himself. He nearly groaned when he heard the chuckle next to him. He hadn't realized he'd spoken out loud.

"Just because you're not doing it doesn't mean the rest of us aren't!" Zeke said with a laugh.

"Who says I'm not?" Four countered, his eyebrow arched.

Zeke laughed again. "Look, I'm not calling that vanilla, missionary shit you and Tris have, sex."

"Again, who says that's all we do?"

"You trying to tell me you and Tris aren't stiffs after all?" Zeke wiggled his eyebrows. "Or maybe you're just the stiff one," he laughed like a loon.

Four shook his head, trying his best to ignore his best friend. Normally, a leader wouldn't review surveillance video but Dauntless was upgrading its cameras and Four, now the head of intelligence and security, wanted to make sure it worked. Turning his attention back to the screen, he groaned again as yet another couple found their way into the little, hidden alcove. "Come on, really? You have rooms, people!"

"Having sex in a place where you could get caught can be exciting," Zeke explained. "I bet this was happening long before Eric used it to pass off shit to those Erudite assholes."

Fast forwarding past another couple having sex, Four merely grunted.

"You know," Zeke said, his eyes on his own screen, "it might not be such a bad idea for you to try and mix it up a bit with Tris. Could be good for you."

Something in Zeke's tone had Four pausing the video feed and looking at him. "What are you talking about?"

Zeke wouldn't meet his gaze. "I'm just saying, when you've been together a while—like you and Tris—it's good to shake things up."

Crossing his arms across his chest, Four turned his chair so that he fully faced Zeke. "Where is this coming from?" His voice deepened, becoming the voice that made his initiates tremble.

"Nowhere!"

"Zeke."

"I'm just saying…"

"Zeke."

Zeke finally looked over at him. "Look, Four, do you seriously want to hear this?"

"Why wouldn't I?"

Snorting, Zeke turned to face him, crossing his arms across his chest, mimicking Four. "Because for years, every time the topic of sex came up, your face turned red enough to explode." Four merely stared at him. The steady, hard gaze normally made people wilt beneath it. Zeke only sighed. "You know that hard-ass, Dauntless-prodigy shit doesn't work on me."

Even though he had a point, Four didn't blink. He did admit to himself that it was hard to be intimidated by someone you'd seen doing all manners of stupid shit with, and he and Zeke had spent plenty of time, usually drunk together, being…well…typical Dauntless men. "Just spill it," he said, shortly.

"I happened to hear Chris and Shauna talking and you and Tris may have come up."

Shaking his head, Four turned his attention back to the surveillance feed to delete the copulating couple. "You were eavesdropping," he said bluntly.

"I resent that. It isn't my fault Shauna didn't know I was in the bedroom and didn't check."

"And you didn't alert them you were there?"

Zeke glared at him. "You want to hear this or not?"

Smirking at the annoyance in Zeke's tone, Four paused the feed and turned back to him. "All right. What do you know?"

"Chris told Shauna that Tris said she felt you were still holding back with her sometimes. She—Tris, that is—is worried one day, she won't be enough anymore."

Four sighed. "Christ, I thought we were past this. I sacrificed myself in Erudite for her. You'd think that would put this shit to rest."

Zeke shrugged. "Bruh, one has nothing to do with the other. She knows you love her but we're talking about sex. We're Dauntless!" He gestured to the screen. "She knows what goes on in this faction and that means she knows what y'all are not doing." Leaning forward with his forearms on his knees, Zeke stared at his best friend. Four was noticeably avoiding his gaze. "Come on, Four. You know good and well you're not doing what you want. Ever since y'all got back from Erudite, you've been treating her like glass. That's not how you started off with her. I've watched you for years and I've wondered what you'd be like if you let go of that control. Tris has got to be wondering, too."

Four squirmed, uncomfortable. He couldn't tell Zeke the truth; that Tris' initial fear of intimacy had given him a lot of concern when they'd finally gotten physical. He had to admit, he found himself curbing some of his own desires in deference to her fear, or rather, what he thought was her fear. Was it possible he'd missed the signs that she was long past those concerns? His stomach jumped at the thought that Tris might be ready to face all that he was, all that he wanted to do to her. He realized a fire had been lit inside him as the thoughts burrowed into his brain.

Zeke turned back to his computer screens. "Just think about it, man. What have you got to lose?"

xXx

He did think about it.

He thought about it while lying quietly next to Tris that night.

He thought about it the entire next day—during the Dauntless council meeting, the meeting with Gus on the new security camera, and during the updates from the supervisors over the wall guard teams.

He thought about it later in the evening at dinner and while hanging with their friends at The Pit.

Then, after Tris had clutched his bare back, writhing beneath him, he thought about it as they lie next to each other in bed, wondering if she was as satisfied as she seemed to be. When she'd come, he couldn't help but think he could make it better, make her come harder.

He thought about it the next morning, during his workout in the gym. The five-mile run, the weightlifting, and the boxing all failed to drain the energy from him as his mind kept circling back to Tris and their sex life.

It had become all he could think about. The idea that Tris might actually want him to lose control, might want him to show her exactly how much he wanted her, had become a tinderbox in his blood.

One he realized was about to ignite into flame.

xXx

Tris gasped as Tobias grabbed her the moment she walked in, pushing her roughly against the door, and took her mouth. There was no hesitation in his lips; the hands that gripped her were sure and strong. Normally, Tobias treated her sweetly, his lips soft and his hands careful and gentle, but not this time. No, this time his lips were hard, his hands strong and aggressive. They raced over her, greedily kneading her flesh while his every touch was possessive and sure of their rights to her body.

And Tris loved it.

It wasn't that Tris didn't like how reverently Tobias treated her body—she absolutely did—but sometimes late at night as they lay beside each other, she wished, if only for a moment, she could break through the walls he put up, through the Abnegation, to find the Dauntless underneath. Thoughts, images, of what he would do to her if she ever got him to lose control featured prominently in her fantasies. Now, without even knowing how or why, it seemed as though she was going to get her wish.

Tris reached up and tangled her hands in his hair, kissing him back just as aggressively as he was kissing her. Tobias' lips trailed down her neck, his tongue darting out to taste her skin, his teeth nipping lightly as his hands trailed under her shirt, yanking it up over her head. He threw it behind him, his lips reattaching themselves to her neck, sucking hard. He was purposefully leaving a mark and they both knew it. A moan escaped Tris and she felt his lips stretch into a grin against her skin in response. He continued down her chest, reaching behind to unhook her bra.

When he sucked her nipple into his mouth, Tris gasped, her head thudding back against the door as she felt Tobias' teeth graze her sensitive skin. He suckled deeply on one breast then switched to the other while unbuttoning and unzipping her pants. Releasing her, Tobias trailed his mouth down Tris' stomach, pulling down her pants and underwear as he descended. He untied each boot and pulled them off, tossing them over his shoulder, quickly followed by her pants. Trailing his tongue up her leg, he then lifted it, perching it on his shoulder. Tobias glanced up at Tris, catching and holding her gaze. His deep, blue eyes were nearly black with desire and Tris felt her breath catch at the feral look in them. He smirked at her then lowered his head.

Tris shoved her hand against her mouth to stifle a scream, vaguely aware that she was still pressed against their apartment door. This was Dauntless, odds were no one would notice or even care, but still, Tris didn't want to call unnecessary attention to them. There was absolutely no way in the world she wanted anything to stop him. Her chest heaved as Tobias nibbled closer and closer to his goal.

Spreading her apart with his fingers, Tobias plunged his tongue into her, pressing firmly then moving in circles. With every revolution, Tris let out a squeak, pushing her hips forward to increase the contact as much as possible. All coherent thought flew out of her head as she felt him slide a long finger deep inside her. She grasped his head, tugging on his hair and in response he slid inside a second, then third finger.

Explosions suddenly burst behind Tris' closed eyelids and she heard a high keening sound, not aware that it was coming from her. Tobias rode out her climax with her, never removing his tongue or fingers until he felt her legs buckle. Standing, he wrapped his arm around her and hoisted her over his shoulder in a fireman's carry.

Striding into their bedroom, he paused only to flip on the overhead light before dumping Tris unceremoniously on their bed. They normally kept the room darkened when they made love but this time Tobias wanted as much light as possible; he wanted her to see everything he was going to do to her.

Tris looked up at him, her gray eyes clouded with lust as she watched him strip. Staring into her eyes, Tobias kicked off his shoes while pulling the black t-shirt over his head. Tris had the nearly overwhelming urge to lick those washboard abs. He unzipped his pants, shoving them and his boxers down just as he'd done with hers earlier. He stood still as her hot gaze wandered over him, up his chiseled chest to his beloved face. Those deep, blue eyes burned into her as he crawled forward and stretched over her, nestling himself between her legs.

Grabbing Tris' hands, he laced their fingers together and stretched her arms overhead as he leaned down and kissed her deeply. Squeezing her fingers, he pushed further inside her, reveling in the way her eyes went blind with pleasure. Tobias held himself inside her, savoring the hot, tight feel of her surrounding him.

"Tobias…" Tris moaned.

Arching one eyebrow, Tobias stared at her. "Yes?" he asked, the deep, husky, insanely sexy tone washing over her, raising goosebumps all along her skin.

"What - what are you doing to me?" She shifted beneath him, hoping to urge him into moving, but his strong body had hers effectively pinned to the bed.

He gave her a small, half smile, continuing to hold his body still, loving the feel of her trembling beneath him. "Do you remember how I once told you my instinct was to push you until you break, just to see how hard I'd have to press?"

Her hips attempted to move in tiny circles, trying to tempt him. She gulped in air, desperate to feel him moving inside her. "Yes," she replied, her voice breathy.

He slid out slowly then slammed fiercely inside of her, reveling in the cry she couldn't hold back. Brushing his lips against her ear, he whispered, "I decided to follow my instincts." Without giving her time to react, he began moving, thrusting deeply, overwhelming her. Bending his head, he nibbled on her collarbone, directly over her tattoo.

Tris' body moved helplessly beneath him, a slave to the driving force pushing them both closer and closer to the edge. This wasn't her quiet, gentle Tobias; this was Four, Dauntless leader, and he was at last unleashing every ounce of the restrained passion he carried on her. Tris gulped for breath as Four moved fiercely within her, his pace quickening. She squeezed his hands, using them as an anchor, trying desperately to keep some semblance of control over herself.

But it was a losing battle.

Four kept up his brutal pace, refusing to let her have any control, demanding her complete and utter surrender. The heat rose until it felt blistering, scorching Tris from inside out. He reached down and hoisted her leg up onto his shoulder, pressing even deeper inside of her, never stopping the driving force of his hips. Maintaining her sanity was impossible, so she gave in, allowing herself to spin out of control until there was nothing but the blinding light of their passion. In that moment, there was nothing, no one but Four and how completely he owned her body. "Four!" Her moan was high pitched, nearly a scream, torn deep from within her as the snap of his hips pushed her over the edge. Electricity zipped along nerve endings until she swore her toes tingled. Tris was already floating in ecstasy when she sensed Four stiffen above her, pushing impossibly deeper, his own shout of pleasure hoarse.

Releasing their hands, Four collapsed on top of her. Tris wrapped her arms around him, hugging him tightly, not wanting to let go of their intense connection. Her head was still spinning and her body tingling as though she'd completed the most intense workout of her life. She had no idea what had caused him to unleash on her as he had, but at that moment, with her body feeling like she was floating, she absolutely did not care. He raised his head and looked at her, enjoying the satisfaction he read in her eyes. He smiled at her a little and she smiled back, raising her hand and brushing a lock of his damp hair off his forehead.

"Wow," she whispered.

His soft smile broadened into a grin, inordinately pleased with himself. "Glad you enjoyed it."

"Oh my God," she laughed lightly. She leaned forward and kissed him. "That had to be the most intense experience I have ever had."

"Well, that's a hell of a compliment," he replied, pride swelling in his chest. He wondered if the smile broadening his lips would now be permanently plastered onto his face.

Tris brushed her lips across his lightly. "Mm. I owe you one, now."

Four laughed. "You think you can top that?" he asked, the challenge clear in his voice.

"Oh, you just wait," she promised. "You'll never see it coming."

Leaning down, he kissed her deeply. "Game on," he murmured against her lips.