You make me week in the knees
"Hey, Molly, could you pass me that test tube over there?" Sherlock motioned to the counter with a tube rack on it without taking his eyes of what he was doing. Molly went there, since she always gladly obeyed him, and sighed. There were exactly four tubes in the direction he was showing to and each of them had a different liquid mixture in them.
"Erm, which one exactly?" she asked. Sherlock looked in her direction for a mere second.
"The left one," he said, not noticing, or just simply not caring, that all of the tubes were placed on the left side of the rack.
"This one?" Molly asked, holding up one of the tubes.
"No, no, no," Sherlock sighed in annoyance, as he stood up and walked towards her. He took the tube from her and at this gesture his long, cold fingers brushed against hers, hot flesh against cold, Sherlock for suddenly something surprisingly different from what he would expect. His heart fluttered, the warm touch of her hand spread from his palm towards his entire body. His head got dizzy and he almost lost balance, because his knees grew so weak so suddenly.
"This one," he said, rather breathlessly, still shocked from the amazingly strange experience, as he put one tube back and fetched another one. He returned to his workplace and with a corner of his eyes looked at Molly, if she noticed his reaction to their ever so slight touch. She didn't, though. She sighed and looked in the other direction from him.
Sherlock dropped the hope of finishing what he was doing and looked around the room to find something that would be small enough to make their hands touch again, for he wanted to feel that foreign feeling again.
"Hey, Molly?" he said when he returned his eyes on the project he was working on, trying not to reveal anything from his voice or body language. "Could you pass me the erlenmeyer flask on the counter?"
(A/N: here it is, another Sherlock's step to defining love ;P it wasn't really easy, trying to come up with something that would make him start actually feeling something ... I hope I did a well anough job, though :P)