Molly was never going to get to sleep at this rate. She turned over and yanked the cord on her lamp. When she turned back, Sherlock's eyes fluttered open to stare at the ceiling.

"What the hell is going on?" Molly growled.

Sherlock steepled his fingers under his nose. "Can't sleep."

She sat up and rubbed her eyes. "Um, yeah, I sorted that out by the twitching. Why?"

He glanced at her quickly out of the corner of his eyes and looked up again. He shrugged.

"Nothing. Everything. Sometimes I revisit old cases and they keep me up. You remember that experiment I did on that corpse? I am still not happy with the results. I am starting to think a whip wasn't the right implement to duplicate the injuries I suspected on the original murder victim. The whip bruises were too dark, too precise. They were not a good match."

Molly groaned and flopped back. "Oh, God, really, Sherlock? That is what, like seven years old? Aarg, I have a lot to do tomorrow."

He bounced the bed as he flipped to his side. "It was a hand. Fingers. Had to be!"

She sighed and tried to recall the case. Then she remembered the strange bruises on the posterior of a dead businessman and how Sherlock had experimented time and again with different BDSM whips to replicate the injuries on a donated cadaver. She rubbed her lips together as she recalled the ferocity of how he had gone at the corpse. It had been one of the first moments she had found the eccentric Sherlock Holmes attractive in his sweaty, disheveled state. It was that exact moment when she had understood his passion and the emotional man she knew he could be.

She stretched out. She would work herself up if she kept reminiscing.

"Sherlock-"

When she looked over at him again, he stared back at her. "Fingers, Molly."

Her mind was momentarily blank as she took in his rumpled curls and plump lips. "What about fingers now?"

"Someone slapped Clive Silverton before his death, hard."

Molly shook the fog of lust from her mind and frowned. "No! There are no way fingers could have left those kinds of marks."

Sherlock appeared unimpressed. "Why?"

She inhaled a deep breath and whipped out her fingers. "Because the bruises were thin! It would have to have been someone with small hands like myself and there is no way I could slap a man of Mr. Silverton's size with enough strength to inflict that colour!"

For a few seconds, he squinted as he thought about her assessment and then yanked off the covers and flipped on his stomach. He wiggled his bare bum.

"Wh-What are you doing?" Molly asked as she scrambled to her knees.

"Conducting an experiment. By morning, bruises should form and we can put this argument to rest. Slap me."

Her chin went back. "No!"

He turned his head and smoothed back his hair. "Come on, Molly. I want you to give it a go."

She swallowed and gripped her own thighs. "But I might hurt you!"

He smirked. "That is kind of the point."

"Sherlock!"

He pushed up on an elbow. His expression relaxed. His eyes flitted seductively over her face.

"Would it help if I told you I like that sort of thing?"

Her lips parted. "Y-You do?"

He nodded, carefully gauging her reaction. "Pain is a stimulant for me, Molly. It causes my blood to surge. It is even more enjoyable to have it inflicted on me by someone else, especially someone I trust."

She wrung her hands. "I cannot believe I am entertaining this-"

"Excellent, shall we?" he dropped to his stomach again and gripped the crossbars of their bed.

Molly gaped dumbfounded at Sherlock stretched out. His back was slightly arched and his legs splayed. His muscles across the broad expanse of his back rippled as he strengthened his grip on the rails.

"I'm waiting."

"I-I'm thinking!"

"Don't think, just spank me."

"Sherlock-"

He peered sideways over his muscular arm. "Do you not have the nerve, Molly?"

"Oh!"

Next think she knew, Molly raised her hand. Still, she couldn't quite commit. Her slap turned into a feeble tap.

Sherlock huffed. "What was that? Was there a mosquito on my arse? I am fairly certain that wasn't even hard enough to render him flightless."

"Male mosquitos don't sting!" She countered.

Sherlock hiked a brow. "Neither do female ones, apparently."

"Eeerg!" Molly gave him a harder swat, this time it made a satisfying crack of a sound and her fingers stung.

"Mmph, god yes," Sherlock uttered, his hips ground down.

She watched in fascination as his butt flexed and he rubbed himself against the bed. A quiver coursed through her belly. He really liked it. She could see in the tense length of his body that he was aroused. That, in turn, caused her sex to pulse to life. Warmth flushed between her thighs.

He glanced at Molly. "You okay?"

She inhaled a sharp breath. "Me?"

He nodded. "Yes, you. You don't have to do this if you don't want, Molly. It's no fun if you're not okay with it."

Molly licked her lips. Her eyes caressed his gorgeous, lean frame and lingered on the faint pink stain she'd left on his cheek.

"Can I try again?" she asked softly.

"Oh, hell yes," he agreed hoarsely.

She scooted to the other side of him and leaned over so her long hair could tickle his back. He lifted his butt slightly. She kissed it quickly and then wound up and smacked him again on that very spot, making sure to whip her fingers in the process. The sound clapped off their bedroom walls. It's echo made her core sting.

"Huh!" his shoulder bunched as he jerked. "More."

Molly spanked him again and again, each spank was even more satisfying. His heavy panting turned into deep moans of satisfaction. His hips kept bucking against the bed. She spanked him until both cheeks were bright pink and her palm prickled with pins and needles. He was almost animalistic in his furious grinding on the bed. She longed to be underneath him.

"Unh, unh, uuuunh," he moaned, "unh, Molly, unh, it feels so good."

Molly couldn't resist leaning down and nibbling on a bit of his swollen flesh. He cursed and next thing she knew, she was underneath him, just as she wished. Sherlock kissed her feverishly and rubbed his painfully engorged cock on her belly. A hand reached between her legs.

"Oh, hell, Molly. You're so wet. You liked punishing me, didn't you?"

"Fuck, Sherlock, if I knew you'd react like that, I would have bent you over my knee a long time ago."

He groaned. "God, I love you."

Sherlock's hand stroked up the back of her thighs and pushed her legs up and apart. Then he guided his blunt head to her folds. Molly's hand snaked around his waist to his rear. Just as he gripped the rails above her head and began to sink into her, she slapped his arse.

"Mmph!" his hips surged forward and he staked her to the bed. "Oh, Christ!"

Molly moaned. His thick cock strained within her body. His balls pressed against her crack. He was harder than she'd ever felt him, like lightning had struck and turned sand to glass beneath his flesh.

"God, fuck me, Sherlock!"

He obliged. His shaft plummeted in and out of her body at a breakneck pace. She kept spanking him as best she could on each cheek until he was grunting and bucking into her like an out of control stallion. It was so exciting, so different, so wildly out of control that she was near a breaking point in record time. Her juncture was so wet and aching that she could barely discern whether he was stroking in or out at any given moment. It was only when he pinned her down, his cock slammed deep in her chamber and met resistance when she ascertained where he was.

"Oh, fuck, I am going to cum," she cried at one point, "I'm going to cum. Fffffuuuuck."

Her orgasm, which had been sparking like a lighter, erupted and flashed like a firebomb. She landed one final spank on Sherlock's arse and his whole body shuddered.

"Molly, uuuuuunnnnhhh, Molly!"

He arched into her, driving her upwards on the bed as his cock thundered its release. As her womb contracted with each pulse of her orgasm, his fluids rippled through his length and into her body. She felt the twitching flesh low on her entry and squeezed him. Another wave of pleasure flooded her insides.

"Oh, fuck, that was so hot," she whispered, her body still vibrated. "Jesus, Sherlock, I don't think I've ever cum that hard."

"Yes, agreed."

Molly's hands left his bum, stroked up his back and she plunged her fingers into his hair. She kissed his cheeks and forehead and then his mouth. He kissed her back between pants. Finally, he sank down onto her and buried his face in her neck.

"Mm, my love, that was spectacular."

"Yup," she breathed, "yeah, it was."

He kissed her neck. "I think I can probably sleep now."

Molly laughed. "On that sore butt? Good luck."

He chuckled and hugged her. "On my stomach then, dreaming sweet dreams of my naughty wife."

She massaged his scalp. "Mm, sounds like heaven."

He raised up and kissed her brow. "It is, and you're my wrathful angel. I love you."

"I love you too, Sherlock."