A/N: I was bored in math and had Sexyback stuck in my head. Logarithms get old after a while, okay?

Shackles

Soul didn't know how it happened. First he was pulling at Maka's hair, her mouth hot on his throat. Then his shirt was coming off, and before he brought his hands down he felt the cold slither of metal settle around his wrists. He realized too late why Maka had placed an extra hook in the headboard a few days ago – perfect for latching the chain of the cuffs on. She pulled away from her position on top of him and dangled the key between her fingers.

"Maka…what…what is this?"

"I was thinking we could…try something new. An experiment, I guess." The slight girl blushed furiously but maintained the nervous grin on her face. "Is – is it okay with you, Soul? If you don't like it we don't have to–"

"No, it's fine, Maka. Just – just keep going." Soul's breath hitched as Maka returned to her spot on his neck, trailing open kisses down to his collarbone. She started tracing her tongue over his scar. Soul groaned and leaned into her, yanking his hands forward to grip her shoulder. He remembered with annoyance that those hands were trapped by a hellish piece of metal.

"Dammit, Maka, I can't touch you like this!"

She paused halfway down his scar and he could feel her smirk along his stomach, her soft breath tickling his skin. Shrugging, Maka made her way to Soul's left hip and hooked her fingers into his waistband. His jeans came off easily, the two mutually cooperating to remove the cumbersome fabric. By now, Soul's manhood was slowly hardening, his boxers stretching with each passing second. Maka grinned and gripped the edge of them with her teeth. Using her other hand to grab the other side, Maka evenly held Soul's very turned-on gaze as she dragged his boxers off.

Contemplating his erection, Maka scooted up to where she could comfortably reach his chest and moved her mouth inches above the tip of his penis. She gently blew on it, eliciting a moan from Soul.

"Maka… don't tease me." He looked up and made a face at her.

"I don't think you're in any position to be making demands, Soul."

He opened his mouth to say something more but gasped instead as Maka closed her lips over the first few inches of his dick and worked her head along it. One hand came down to cup his balls; the other squeezed the muscle on his chest. Pre-cum and saliva slowly dripped down his length. Soul bucked his hips into her mouth, desperate to satisfy the growing desire within him. He didn't know it, but his moans and whispered curses were driving Maka insane. Moments before he climaxed, Maka harshly tore away and pulled back, sitting up on her heels.

"What the hell, Maka?!" Soul jerked his head up, one eye opened in confusion and irritation.

"I just remembered…Shinigami told me you've been cutting class again." She wiped a hand across her mouth, biting her lip to suppress a grin.

"You don't need him to tell you that, dummy."

"Well…I guess I'll just have to punish you for it, then." Maka batted her eyelashes innocently at Soul but her widening smile betrayed her thoughts. She stood and walked off the bed and turned her head around to look at her weapon.

"Watch me, Soul."

Before he could protest, Maka had stripped off the remainder of her clothing, leaving herself only in a lacy pair of bra and panties. She easily unhooked her bra in a second, but took her time peeling it off her chest. Soul gasped as she undid the knots at the sides of her underwear, the moonlight enveloping her body in a soft whiteness. Her nipples were already perking up in the cool air. Catching his eye, Maka slowly slid her hand down her stomach to skim across her clit. As Soul stared at her, Maka began to touch herself. Her moans nearly drowned him in his desire, and he furiously thrashed at his restraints.

"Dammit, Maka, stop it!" he yelled at her. "I can't take this!"

"I'm sorry, did you say something, Soul?" The way she peeked out at him and called his name was killing him.

"Stop – stop, let me go. Let me touch you. Please, Maka." He knew it was uncool to beg, but Soul hardly had any choice left.

"Make me." She took a step closer.

"Let me touch you, Maka."

"Say it again." Another step.

"Let me touch you, dammit!"

She was practically on top of him now.

"And why should I let you go?"

"Because you're the sexiest Meister alive…" he muttered.

"What was that?" She pressed her breasts on top of his chest, and Soul let his thoughts out.

"Because you're driving me crazy! Because you're my bookwormish, flat-chested, irritating, cute, brave, gorgeous, sexy Meister! Because I can't handle what you, only you, can do to me! Let me go, please, please, Maka!" he pleaded. Maka checked their resonance link and gasped at the force of his desire for her. She grabbed the key from the nightstand and held it between her lips.

"Say my name again."

"Maka. Please."

"Again."

"Maka."

"Louder!"

"Maka!"

"LOUDER!"

"MAKA!"

Click.

He was on top of her faster than she could blink. Sliding a hand down to check her wetness, Soul grinned and eagerly shoved himself inside of her. Maka groaned in pleasure and wondered what other kinks she could convince Soul into. She made a mental note to thank Blair later.

Soul, oblivious to her thoughts, was pounding into her, running his fingers up her body. Maka arched her back into his touch, feeling his hands everywhere – her hair, her shoulders, her back, her breasts, stomach, hips, ass, turning her on more than she could believe. Soul played her like a piano, driving her body towards a new world. Reaching up, she dug her nails into his shoulders, feeling her climax approaching with his thrusts. Two final pumps and she was burying her face in his neck, every muscle in her body clenched with the pleasure flooding her body. Everything was the feel of Soul in her, on her, his hot breath scorching her skin. Soul followed her not too much later, and their hips collided as he continued to buck into her.

Eventually, the waves of their orgasms faded and Soul flopped out beside Maka. He turned and pressed a kiss against her lips, still full of passion. Maka snuggled into his chest, her hair clinging to the sweat on her face.

"We should do that again sometime," she mumbled.

"Agreed. But next time, I'm punishing you."

"Okay." Maka was already half-asleep. She failed to notice how Soul gently guided her arms up to the metal links that had held him captive. Locking them around her wrists, he tucked the key beneath the bed. If he was punished for cutting class, she would pay by missing it. Pulling up the blanket around them, he settled his head on top of hers and whispered to her, "Looks like Stein's lectures will have to wait, Maka. Tomorrow morning, class is in session…with Professor Soul leading the discussion."