A/N: I just read a lot of M-rated fanfics, and I'm horny as hell, so I decided to give a lemon a shot.

First sex scene, so please don't flame. Let me know if it's any good.

Tris had an ache, somewhere in her lower belly. She had heard from Christina that this meant something, but she didn't know what to do about it. She tried pleasuring herself. Nothing. She couldn't even come.

She and Tobias hadn't reached that level in their relationship yet, but perhaps they should change that. And Tris knew that he would never make the first move, worried that he would scare her off, so she would have to take matters into her own hands.

She dressed in a black mini-skirt, tank top with spaghetti straps, and heeled, knee-high boots. She left her hair tumbling down her back in loose waves, the way she knew Tobias liked it best.

Tris let herself out of her Ambassador apartment and walked to Tobias's, three floors down.

Tobias was making a simple dinner—grilled chicken—when he heard a knock at the door. He opened it and his jaw dropped. Tris stood in the doorway with a bottle of wine in her hand, her hair falling over her smooth shoulders, in a skirt so short it should have been illegal. She wore high-heeled boots that made her long legs look even longer.

He felt a tightening in his pants as he opened the door further, letting her step inside. She walked past him into the apartment, the silky skin of her arm brushing against his, doing nothing for his hard on. She smelled amazing, like lemongrass. He could have stood there and sniffed her for hours, but he realized he hadn't moved for a few seconds, so he shut the door and stepped back into the living room.

"What are you doing?" He asked, his voice husky. He cleared his throat. "There's a meeting tomorrow. Don't you need your sleep?"

Tris had set the wine on the table, and she turned to him, so close he could see the blue-grey of her eyes. She lowered her voice a few notes, and said seductively, "I need something, all right."

Tobias swallowed as she stepped closer. He could feel the heat emanating from her body. The material of her shirt was so thin he could see the peaks of her hardened nipples. She took one more step, and those nubbins were pressed against his chest.

He could feel himself hardening even more, and he angled his lower body away from her, hoping she couldn't feel it.

Tria reached up and looped her arms around Tobias's neck, leaning in for a kiss. He gladly obliged, but pulled away far too soon for her liking. "Tris..."

She pouted. "Don't you want this?"

His eyes widened. "Of course I do! It's just—are you sure?"

Tris nodded, and Tobias couldn't resist pulling her to him and kissing her hungrily, pressing his arousal against her stomach. She inhaled sharply, and he was afraid for a minute she had changed her mind, but instead she ground herself against him, eliciting an appreciative groan from him.

"Gods, Tris, feel what you do to me?"

She hummed affirmative, and pulled him toward the bedroom. Tobias lost his shirt, somewhere along the way. Once they were in the bedroom, he turned to her. "Last chance to change your mind, Tris. After this, I can't be held responsible for my actions."

She growled and bucked her hips against him, earning a sharp hiss. He tugged at the hem of her tank top, and she pulled it off, her bare breasts bouncing free. He was now rock-hard as his eyes roamed over her mounds.

Tobias's mouth went dry at the sight of them.

They were small, but perfectly proportioned for her petite frame. He pulled her skirt down, revealing that she wore nothing underneath. Her crotch had sparse, blonde hairs that almost appeared invisible against her pale skin.

"No panties? What a naughty girl."

Tris moaned as his long fingers skimmed her pebbled nipples. She reached down and cupped Tobias through his jeans that seemed uncomfortably tight. She fumbled with the button, and slowly unzipped him. He wore tight black boxers underneath, which did nothing to hide his erection.

Her eyes widened at the sight of him, straining against the material of his underwear. He was at least nine inches, and wide. How would that ever fit inside of her?

Hesitantly, she stroked him, making him growl and throw her onto the bed. He hovered over her naked body and enveloped one of her nipples in his mouth.

Tris gasped as Tobias's warm mouth closed over her nipple. She arched her back instinctively, thrusting her breasts toward him. His tongue laved at the tip, and she threw her head back into the pillows. He switched to the other one, lavishing as much attention on it as he did the first one, then trailed open-mouthed kisses down to her mound.

Tobias could smell her arousal. It smelled wonderful, like honeydew. He stopped with his face level with her folds. He flicked his tongue out to taste her, and she groaned appreciatively.

He licked her entire slit and watched her shiver at the sensation. He took her sensitive button in his mouth and swirled his tongue around it gently. Her head had raised to watch him eat her out, but now it fell backward onto the pillows, her mouth open wide, her eyes squeezed closed.

He had been with girls before, but none so responsive to his ministrations as Tris, and none quite as beautiful as her. He knew she thought herself plain, but she wasn't. Her blonde hair had a natural wave to it that most girls would kill for, her eyes lit up and shone when she was excited or pleased, she had a slight hourglass figure, and clear, smooth, silky skin that he wanted to lick all over.

Perhaps he would later. The night was still young, after all.

Tris groaned as Tobias' warm tongue lapped at her slit. He paid special attention to her cliit, making her arch her back in ecstasy and squirm. Finally she couldn't hold back anymore, and she came with a loud cry.

Tobias kissed his way back up to her neck, sucking on her pulse point and leaving a light purple hickey, clearly claiming her as his. He bit her shoulder sharply, then quickly soothed the spot with his tongue.

Tris gasped as his mouth continued to administer small bites around her throat and shoulders, and became even more aroused. She rubbed her thighs together, desperate for friction.

"Please!" She moaned, then broke away from his mouth, pushing him down onto the bed and kneeled above him. She pulled Tobias's boxers down, exposing his rock-hard erection, pre-cum glistening on the tip. She had never seen a penis before, so she examined it curiously, then wrapped her hand around it.

Tobias gasped and hissed softly as Tris's small hand wrapped around him. He fought the urge to buck his hips. Tris leaned down and took a tentative lick, making him inhale sharply.

Tris smirked as she watched Tobias's head fall backwards, his eyes shut tightly. She opened her mouth and fit an impressive amount of his cock inside. Tobias couldn't fight anymore; his hips jerked upwards, filling her mouth to the max and making her choke slightly.

She quickly caught on, and bobbed her head, sliding her hand around the part she couldn't take into her mouth. Tobias knew he was close, so he tried to push Tris off him, but she was having none of it. She moved even faster, reaching up to fondle his balls, and he exploded.

His cum wasn't exactly delicious, Tris decided. It was thick and creamy, but it tasted like flour and salt, with a slight bitterness to the aftertaste. She discovered that she liked giving Tobias head. She knew most girls didn't, but watching Tobias lose control was oddly satisfying.

Seeing Tris with a few drops of his seed around her mouth made him instantly hard again.

Tobias was lost in a haze of lust for the petite blonde girl kneeling over him. He pulled her left leg over his torso, making her straddle him. As she looked at him, confused, he lined himself up with her and thrust up.

Tris gasped as he broke something inside her, and Tobias mentally cursed himself for not considering she might be a virgin. Somehow, that thought turned him on even more.

"Shit, Tris, I'm so sor—"

He was effectively cut off by Tris starting to ride him. "Fuck," he moaned, trying not to cum right then.

He watched through half-closed eyes as she bounced on his cock, her pert breasts jiggling with each motion. He began thrusting, and Tris moved faster.

Tris rolled her hips experimentally, and he groaned. She cried out when he brushed against a sensitive spot inside her, and he made a mental note of the angle.

Tobias could feel himself getting close, and he pounded up into her harder, hitting something deep inside her each time.

Tris let out a small shriek as her orgasm washed over her, and her walls clenched, milking his own pleasure. She collapsed on top of Tobias, her legs unable to hold her weight anymore.

"Fuck, Tris, that was amazing," Tobias said, trying to catch his breath. He didn't think he'd ever orgasmed that hard in his entire sexual experience, which was quite small, actually.

She hummed in agreement, her throat vibrating against his arm. She traced lazy circles on his sweaty chest, making him squirm.

Tobias let out a hoarse laugh. "I think I burned the chicken."