Hello y'all!

This is smut. My very first smut, and I hope you'll like it. Shout out to my Beta-reader Pokypup49 (on AO3), who've been very nice with me! Thank you again!

This OS has been written for the "Nuits du FoF", on the theme "Règle" = Rule. I had another choice, because règles means period too, but I'm already writing something about that, so here I am, with a fic that breaks rules (some have already been broken, but others will be).

The idea of the safe houses is inspired by lantur's latest OS (go check it on AO3!), and the title comes from "On fire" by J. Bernardt (a song that I discovered while writing this).

Disclaimer: I do not own anything from Fullmetal Alchemist

Now, it's time to enjoy!

When they had begun, they had decided to set rules so they could stay as discreet as possible.

Never meet at the other's place.

Never tell their feelings.

Roy and Riza had scrupulously followed these rules for four years, seeking refuge for a weekend in one of the houses the Colonel had bought to make a safe house somewhere in Amestris, in a village inn during a cover mission, or in a shabby hotel in East City or Central, dressed up to avoid any suspicion. All precautions were taken to allow them to give up to the burning desire they couldn't resist.

They knew for a long time now how to decode the messages in the eyes of each other, uncovering the festering ember and igniting it when they couldn't resist anymore. When this moment arrived, they took thousands of paths to find themselves alone. They would forget and put aside the military and the rules for the time they needed to cover again the desire by their kisses, their caresses, their moans.

When they came back from their orgasms, breathless, naked with sweat-salted skins, they didn't speak. They were certain that the moment they broke the silence, all the secrets that lay on their hearts would come out.

Several times Riza had cut Roy with a feverous kiss, preventing him from uttering the words. Roy had done it too and this interruption had often led them into another burning embrace that left them ecstatic.

However, this time it was different. This time Roy couldn't resist. He knew it was his last chance to convey his feelings to her. It had been months they hadn't been able to see each other, split because of Roy's recklessness and Bradley's orders. They were exhausted.

As they left the cemetery and walked to the car, Roy caught Riza's hand, intertwining their fingers. She raised her eyes and forgot to breathe when she met his pupils, darkened by his desire.

"I can't bear it anymore, Riza," he breathed in a husky voice. "I want you; whole of you."

Riza glanced at their hands then at him. She looked at those eyes she loved so much, she'd missed so much for months. She gulped, melting under the intensity she could read in them. How many times had she dreamed about their meeting when Bradley and the homunculus' threat wouldn't exist anymore? She felt Roy's thumb stroke her palm, and she shivered, from her arm to her spine, until it reached her belly. And there she was burning.

For all of the evening, since Roy had met their small group in the tunnels under Central, she'd avoided thinking about him that way. Now they were alone since Breda and Fuery had stayed with Mrs. Bradley in the warehouse that was their base camp. They were alone, and all her desire of him had awoken with only one contact.

One part of her mind tried to reason her. It's not the time. You have more important things to think about right now. The other part shouted to knock down all walls, to break rules, to give up into tentation. Tomorrow all will have changed so what use is it to wait more?

Screw reason. Riza gave up any fear and dived into Roy's eyes. "Then take me," she whispered.

As if he'd waited for this moment all this time, Roy captured her lips, crashing her between the car and him, entangling his fingers in her blond strands. Riza replied eagerly to his kiss and gripped his dark coat with all the strength given by her longing for him. With a caress of his tongue on her upper lip, he asked for her mouth. Riza invited him wholeheartedly and lost herself in the taste of his mouth and the smell of his skin. He'd drunk whisky at Madame Christmas' and she could taste the bitterness of it one hour later. Roy's hand wandered on her back, her belly, and one of them landed on her breasts and softly massaged one. A moan arose in her throat only to be interrupted by the dance of their lips. Her insides were aching with desire and when Roy pressed even more against her, she felt his hardened cock on her belly.

One of his hands left her back, and at its place the cool metal of his car pierced through her jacket. It didn't last long since the door was quickly unlocked. Roy pushed her gently through the opening, until she was sitting on the back seat of the car.

Roy's hands came back to her body, and with a few pushes on her chest and breasts, which suddenly felt tight in her bra, she retreated until her back touched the other side of the car. The "clang" of the door closing was muffled by the seats, and Roy hungrily kissed her again. He kneaded her chest, provoking hot waves that diffused in her belly and to her crotch.

"I'm hot," Roy whispered in a hushed voice.

Riza's eyelid opened. She'd closed them to feel Roy's ministrations more intensely. She anchored her eyes in his. They were shining under the light of a lamp post. "You've got too many layers of clothes," she breathed on his lips.

She took the lead and blew kisses on his cheek, his neck as she rid him from his coat, soon after followed by his uniform jacket falling to the car floor. Then Riza focused on kissing a spot on Roy's neck, just above his collarbone, where she knew he was sensitive. Roy's groan aroused her even more and she didn't know if she could wait anymore.

He took back control, grabbing her wrists in his hand above her head and took off her jacket in one strong move. With a "click", her hairpin was on the floor, forgotten, and Riza's hair fell on her back and shoulders. Lying her on her back, Roy kissed her again, and his hands ventured on her belly, under her T-shirt. He provoked delightful sparks everywhere he touched her. While he lifted her bra and caressed, massaged, her breast and teased her hardening nipple, his other hand went down to unbutton and take off her trousers.

They shared a glare full of desire, and Riza understood what he intended to do when she felt Roy's fingers on the wet clothing over her slit. She nodded and after one last kiss, Roy slid on her, kissing her skin everywhere he could as he descended along her abdomen, insisting on the places where she was the most sensitive.

Panting, Riza enjoyed each contact, shivering under his warm lips, his wet tongue, his gentle hands.

Expertly, he took one of her boots off, then the second, and her trousers followed too. The brush of his fingers on her calf, in the back of her knee, on the delicate skin inside her thigh, and his soft or pressing kisses made her moan and tremble. Her breath caught in her lungs when his lips landed on her groin.

"Roy, please…"

Roy heard her plea and set the cloth of her panties aside. With a single contact of his tongue on her clit, he sent a whirl of pleasure in all her body, and she whimpered loudly. "Roy…" she protested when he pulled away to slide her panties along her legs with an appreciative whisper.

He gave her a toothy grin. Oh, how she loved him in these moments! He dived back between her open legs. He licked, teased, nibbled her clit, and pressure raised inside her. He massaged her ass, exacerbating the tension in her belly. Her legs trembled when one finger entered her pooling slit. He insisted on the places where she was most sensitive and he inserted a second finger and started moving them back and forth, slowly.

It was so good, and Riza was losing her mind at each thrust of his fingers, each flick of his tongue. She hadn't felt this way for months. When she was alone at home, she'd tried, with her fingers, caressing herself, to find what Roy gave her, but she hadn't reached the same level of pleasure.

Riza gripped the edge of the seat and her other hand wandered on Roy's messy hair. She breathed heavily and her mind turned blank as her orgasm built inside her. In a blissful burst of pleasure she moaned and arched her back, pressing her head on the seat under her. Her legs trembled endlessly on Roy's shoulders, and her vagina tightened around his fingers that hadn't stopped dancing inside her.

Waves of pleasure came on after the other, leaving her panting between Roy's hands. He slid his fingers out of her and she fell hollow. He rose to her level and they shared a long salt-tasting kiss.

Riza pushed him and kneeled on the seat, fixing her eyes on Roy's, and swept her fluids from his lips. "Your turn," she whispered, and her voice sounded laden with desire.

She resumed her kisses in Roy's neck, unbuttoning his shirt to the hem. She descended as his skin appeared under the piece of cloth, licking him, sucking his sweat. She stayed longer on the scar on his left flank, drawing sighs and groans from his mouth.

She reached his belt and began to unbuckle his uniform pants that were twisted by his swollen cock. Boots and pants followed his shirt, and they were almost totally naked in front of the other.

"I missed you," Roy breathed. Riza was thrilled to see him hold back a moan when she brushed lightly against his crotch.

"Me too," she replied. "All alone I'm not enough."

"All my life you'll be the only one I want to make me react like this."

Roy's declaration caught her breath. They'd promised not to expect anything from the other, but they knew they could give way more than what they might now, and it was the first time Roy said it out loud.

However, she knew she couldn't handle more from him, and kissed him to prevent him from doing so. Soon after, their tongues were dancing languidly, and Roy took off her black turtleneck. In the same move, he unhooked her bra and slid it along her arms. Then he bent over her breasts and worshiped them with his tongue. Riza threw her head back, happy with his ministrations. He nibbled her left nipple and licked the areole, while Riza bit her lower lip. Little noises escaped her as he kneaded her other breast. She tangled her fingers in his black strands, and her right hand landed on Roy's midsection, slid to the hem of his boxer shorts, and stroked his erection. He nipped her tit harder, and Riza whimpered.

"I'm sorry!" he said, pulling away.

Riza shook her head. It wasn't too painful, and anyway he would make up for it, wouldn't he? She winked at him mischievously.

His boxer shorts were set aside, and Roy's erected cock appeared in plain sight, ready to serve her. Gently, he pushed her on her back and kneeled legs apart in front of her pussy pooling with desire. "I've got nothing with me," he whispered, uncertain. "Are you sure you…"

Riza nodded. She'd got her annual injection two months ago, she would be fine, she assured him, smiling.

She gasped when his cock touched her clit, once, twice, and panted, breathless.

She could never get bored of these moments with him.

It was one of her last coherent thoughts before Roy entered her, slowly, sliding without any resistance until he filled her whole. Riza moaned. He was in the right place and she wished he would never leave it.

Roy began to move. She breathed faster at each of his thrusts and moved along him with her hips. Their pace increased, and the flapping sound of their skins against the other's, their haphazard respirations, and their moans and groans filled the space of the cabin. Roy's hands wandered on her belly, her hips, her rear, her thighs, and each brush on her skin was another rock on the unsteady pile that would crumble when she would have reached her peak.

Roy slowed a bit, and she felt it. She was almost there. "Roy…" she breathed jerkily.

Instantly Roy's fingers pressed on her clit and she came with a piercing scream, her eyes closed, her back arched and her hands caught Roy's by instinct. She felt her inside pulsing around him as her orgasm shook her. He resumed a steady, fast pace, and soon after came with her in a powerful grunt, twitching inside her.

"I love you, Riza!"

Her eyes jerked open and she pulled Roy to her into a burning kiss as their orgasms consumed them.

Lying in the warmth of the car, naked between Roy's naked form and the back of the seat, Riza enjoyed the touch of his fingers on her back, playing with her wet hair strands. She knew they couldn't take anymore time, but it was a moment she loved so much, because it was so simple.

Roy's words hit her suddenly.

He'd declared his love for her.

She pulled away from his embrace and stood on her knees and hands above him, gazing at him seriously. "Roy…" she began. But nothing else came out of her mouth as she dived into her lover's eyes.

It was the first time he'd told her he loved her since the day he'd left after he'd deciphered the tattoo on her back. This time like the first one they'd made love to each other knowing that the only authority that could have stopped them couldn't do it anymore. The military laws were still here, but that hadn't stopped them for years. Riza softened and bent over Roy.

"I love you, Roy," she whispered in his ear.

The kiss they shared was so sweet she felt like she was melting against him.

They would deal with the consequences of broken rules later, when they would have assumed the consequences of their Coup. For now, tonight, they had a plan to execute and a country to save.