Author's Note:
Hello! This is my first fanfic so please be patient with me, I know it's a bit awful but I aim to make it better, keep in mind I haven't written in a long time!
Thank you

The past couple of days had been rough on Sam. It was evident in his tired eyes; the bags underneath them heavy from lack of sleep. No matter how hard he tried to get to sleep, there was always that voice waking him, taunting him. For a change, it wasn't Dean.
"Try and get some sleep, Sammy." Dean told Sam comfortingly, patting his shoulder.
"Dean, let me come with you." Sam pleaded.
The puppy eyes almost worked on Dean, but he knew that Sam's safety was his top priority.
"C'mon, Sam. No." He said softly, addressing his younger brother as he packed his small duffle bag full of supplies.
Sam sulkily lounged against the headboard of the bed, his lanky frame weak with exhaustion, his arms folded stubbornly.
"Wouldn't it be safer for me to be with you anyway? So I don't do anything, you know... stupid?" Sam questioned, worriedly.
"Look, I'm not far ok? You have your cell with you, if you're in trouble just give me a call. I really wanna be here lookin' after you Sammy, but its urgent."
"No, no I know. Go." Sam urged, waving his hand dismissively.
"Remember to lock the door as soon as I go out. I mean it, Sam." Dean warned.
"Yeah, yeah I know."
Dean exited the motel, closing the door firmly behind him. Sam listened as the engine of the Impala stuttered, before he sat up off the bed and locked the motel door as Dean had asked. He stopped for a moment and took in the sound as the Impala pulled away, the sound of gravel crunching under its sleek tires. Suddenly he felt so alone – so vulnerable. He always felt that way without Dean. He made this whole... situation a lot easier for Sam. He made everything easier. But now that he was working a case without him, Sam felt afraid.
With a sigh, Sam slouched back onto the bed and rested his head on the firm motel pillow, trying to get to sleep. He curled up into a ball, wrapping his arms around himself before his aching eyes fluttered slowly to sleep.
"Sammy." A familiar voice sang, stirring Sam from his slumber.
Sam's hazel eyes flickered open, his eyebrows knitted together.
"Hmm," The voice hummed. "Hello Sam."
Sam shot up in bed rigid, his shoulders stiffened at the sudden realisation. That voice turned his blood to ice, no matter how many times he heard it.
"Lucifer." He spat.
"What's with the bitter tone?" Lucifer purred, advancing closer to Sam as if he was prey.
"This isn't real. You're not real." Sam reminded himself, springing off the bed. He got up so quickly that the room became an array of stars and flashing lights. He dizzily rocked on his heels.
"I never left, Sam. You're still in the cage... with me." Satan's head cocked to the side, a smirk playing on his lips.
Sam backed up against the wall, grabbing his knife from the bedside cabinet.
"Stay away from me." He warned.
"You can't kill me. I'll just keep coming back." He laughed, moving closer.
Sam gripped the knife tightly, watching as the shadows in the dingy lit motel danced menacingly on the Devil's face.
"Try it." He whispered down Sam's ear.
Sam brandished the knife, plunging it deep into his chest watching as the apparition disappeared, shimmering like a mirage. Sam sunk against the wall to hear eerie laughter echo throughout the room. It bounced off the bathroom pipes and rang in the motel vents.
After a few moments, he appeared again as clear as before.
"Leave me alone." Sam begged. "Please just go away."
He was almost on the brink of tears, he was drained and frustrated and wanted to be left alone. He raked his big hands through his messy, dishevelled hair in an attempt to shake him.
"GET OUT OF MY HEAD!" He screamed, bashing the heels of his palms to his head.
"Why would I want to do that, hm? You're my favourite toy, Sam." Lucifer told him smoothly. He kneeled down in front of the Winchester who was slumped on the floor, defeated. He lifted Sam's chin, making him look up at him.
"It gets awfully lonely down in the cage without you, bunk buddy." He said, widening his eyes in mock innocence. His cool, blue eyes glimmered in the light.
"Go fuck yourself." Sam snarled at him, his voice dripping with such venom.
Their faces were just inches away from each other.
"I'd be careful what you say to me, Sam." He spoke soft and low, dangerous and menacing which caused Sam's stomach to twist nauseously in pure fear.
Lucifer ran his finger down a lock of Sam's hair before continuing as before. "Alastair didn't even have as much fun with Dean as we had together."
Sam grimaced at the mention of Alastair's name, the very thought of him hurting Dean made him ball his fists and made his knuckles turn white.
"Alastair hardly got a sound out of your brother."
He gritted his teeth again, his nostrils flaring as he stared at the Devil with such hatred.
"You didn't last very long, did you Sam?" He smiled, licking his teeth deviously.
Sam face suddenly flushed deep red as he tried to forget the memories of the cage. His ears were burning; it felt like he was on fire. Flashbacks flooded through, all a blur of heat and bodies.
"I did a good job with you." Lucifer said, leaning in slowly.
A cold, icy hand slid slowly under Sam's shirt, making him shiver under the touch.
"Stop it." Sam breathed, pushing his hand away.
"I know you like it, Sam. You can't lie to me." Lucifer carried on. "I'm 'in your head,' remember."
Sam felt his fingers teasingly trace the line underneath his boxers and he clenched his fists to try and stop himself from getting aroused. His hand slipped further and further until it was around the base of Sam's hardening cock. Gritting his teeth, Sam tried to bite back a moan.
"Come on, Sam." Satan said softly.
An involuntary grunt escaped Sam's lips as he squeezed his eyelids together in ecstasy, Lucifer's hand pumping slowly around his shaft.
"That's right. Moan for me." He ordered.
Sam's hand grasped at Lucifer's shirt as he whimpered, his eyes rolling back into his head.
"I don't need consent from you, Sam. You've already said 'yes' to me so many times before." He growled down Sam's ear, yanking his hair and forcing his head back. Lucifer took the opportunity to lean in and bite down on Sam's exposed neck.
"F-Fuck." Sam stammered. "Ah."
Sam's eyes flickered down where the Devil's hand work expertly around him as it had done down in the cage.
"What did you tell Dean? That you were tortured?" Satan scoffed.
Sam nodded, gulping down his gasps, his Adam's apple bobbing up and down.
"You wouldn't want Dean to know that you were fucked by the Devil and you loved it." He stated, the corner of his lips turning up into a sly smirk.
Sam felt a pang of shame, felt guilty for enjoying it as much as he did.
"You love it, don't you Sam?"
Sam didn't want to admit it, but he did.
"Yes." Sam choked out.
"Good boy."