A lot of things happened at once.

Sherlock felt sparks flicker at his lips, a slight numbing feeling, the sides of his neck grew flush. It was the flood of heat that surprised him most. The Woman's kisses had been sleek, elegant, cool. Janine's had been enthusiastic, wet, overblown. This was different. This was science. Molly's kiss was electric, magnetic, it was a force of physics that drew him in and set him to boil. Sweat blossomed under his scarf, and never before had his clothes felt so burdensome.

Molly broke away, pink-cheeked and imp-eyed. Sherlock watched her mouth curve into a wry smile, unaware of his own open-book expression of shock. He gathered her up with both hands, dropping his books, making her drop her tote bag onto the dark, creaky wood floor. His mind was racing, taking in new data. Touch. She felt small, strong, soft, curving. His hands skimmed the edges of her over her jacket. The ends of her long hair slipped around and between his scorching fingers. More.

His eyes searched hers for approval, but he didn't want to make a mistake.

"May I kiss you?" he asked, his brain reporting that his body temperature had risen alarmingly, and that his heart rate was above average and climbing.

"Of course," she said breathily, reaching up and twining her arms back around his neck. He lowered his mouth to hers, each breath painful in anticipation. Her felt her fingers run through his hair, sending shivers down his spine. Their mouths met, opened, and the heat inside him grew with each taste of her. She pulled him closer, and he braced his arms on either side of her head against the bookshelf behind her.

The electricity crackled inside of him, the magnetic force of his attraction to her irresistible. He felt overwhelmed by the unfamiliar sympathy with another person, the desire to for intimacy. Each touch made his appetite grow, making him aware for the first time of the hunger he had derided in others. Finally he understood the pursuit of satisfaction, and the lengths one could go to to achieve them.

"God, Sherlock," Molly moaned, "where have you been keeping this?"

"Is it always like this?" he asked between kisses, sliding a hand down her body and pulling her knee up inside his jacket to hook on his hip, bringing them closer yet. His body felt aflame.

She rocked into him, and he recognized he was painfully erect. His brain raced for a foothold, pulling in the book titles in front of him, the dozens of shades of amber-red-auburn-brown-copper-tea that made up her hair in the lamplight, the blend of smells of book, decay, wood, plaster, wool, his sweat, and her normal scent amplified by her own pounding blood and physical excitement.

"Never," she answered, lost. He ran his hand from her knee to down under her thigh, drawn to the heat at her core. The sighing sound she made as he brushed the central seam of her trousers guided him to do it again, pressing more firmly with each stroke. Concentrating as to not break his rhythm, he moved his other hand to her blouse, gently cupping and massaging one breast through her shirt.

Molly gasped and arched her back, kissing him hard while she quivered against his fingers. He held her tightly to him, deep in his own swirling mental galaxy of sensation that shut out the rest of the world. The pressure of her lips eased, became languid and melty. He could feel the rise and fall of her chest against his, deep with excitement.

Palming her own breast harder than he would have assumed she liked, she pulled the side of his open greatcoat to encompass her. She moved his hand gently from her thigh, and guided it back down to her knee for support.

"Tell me when to stop," she whispered, knowing he wouldn't. The button to his trousers came open with a flick, the zip down, and he felt her warm, clever fingers stroke him. He was wet, painfully hard, and filled with a desperation for completion that he'd only ever felt for illicit drugs before. The electricity that Molly had created with her mouth when they'd kissed grew throughout his body, and within a few moments he was at a precipice.

"Please," he begged softly, resting his head on her shoulder, his fingernails digging into her leg and the bookshelf. Desires filled his imagination, filling in blanks, wondering what if would feel like to be inside of her if just her hand was already this glorious, the impulse to remove all clothing and touch her skin, to allow himself to be consumed by the heat of his body. He wanted to hear her, wanted to hear her thoughts and wants, to have her describe how she felt as their bodies met, so lose herself to it.

She kissed him and let her tongue slide along his, and he imagined tasting her everywhere. With every stroke she massaged her breast with him.

The suddenly his mind was silent. He broke their kiss and bit his lip to stop himself from crying out as she sent him over the edge for the first time. He pulsed, overcome, his ears ringing. There was a sticky warmth in his shorts that would become annoying shortly, but for now there was only her. They kissed over and over, unable to stop, unsatisfied even in their completion.

"No, man, don't go back there yet. I'm watching a free show on camera four."

The voice belonging to the teenage boy working the cash floated to their spot in the back of the labyrinth of bookshelves. Sherlock scanned the perimeter. Sure enough, a discreet black orb hung in the corner. The floor on the other side of the bookshelf creaked as someone shifted their weight.

He let Molly's leg slip down to the floor, and she put his trousers to rights. He took her hand, still damp with his fluids, and half pulled her out of the shop. Molly scooped up her tote bag and Sherlock's books on the way, and they bumped aside the interloper who had been about to discover them.

The night air did nothing to cool Sherlock's temperature.

He glanced down at the woman at his side, who had a slightly glazed smile and mussed hair in the glow of the streetlights, and he could think of no satisfactory course of action besides taking her to his bed and consummating this intense intimacy between them.

She waved a passing cab, and it slowed.

"Yours or mine, Sherlock," she asked, straightening her blouse, but then undoing the top button so that the sides fell to rest on top of each breast.

"Mine," he decided. They slid into the back seat of the cab and Molly gave him the Baker Street address. She looked out the window and spoke to the glass.

"Well, we can strike the question of sexual compatibility off the list. I have to ask though, Sherlock, why is it that you don't want to have sex before marriage? I need to know whether to stop you if we get carried away so you don't hate yourself or me in the morning."

He thought a moment about that, about the risk of getting carried away, about whether his reasons were still important.

"If I let someone in that deep," he said slowly, "it could only be because they're there to stay forever. Nothing less."

"I can't marry you while you're still missing the most crucial and basic requirement," Molly reminded him.

His fist clenched with frustration as he tread the well-worn mental path of what she could mean. Dammit.