John wasn't always able to get away, but he did end up sneaking out his window more often then not. Sherlock was always waiting for him at the school when he got there. The next two weeks were a heady blend of knowing smiles and hand-holding during the school day, an icy silence from his parents in the evenings, and a frantic mess of kisses as soon as he and Sherlock got their privacy. It was still too cold outside to do more than slip hands under each other's shirts and jackets, but Sherlock was definitely getting better in the snogging department. Also in the licking-that-perfect-spot-on-John's-neck-to-make-him-writhe department. John hadn't known he had such a sensitive neck before, but Sherlock was incredibly thorough in his exploration.

"Mycroft's gone," Sherlock announced on a Friday night when John hadn't been able to get away until especially late. "Out of town for business all weekend. How are you at scaling garden walls?"

Hell yes. John's fingers literally itched to get Sherlock out of the cold and out of his posh coat. And into a bed, preferably, although he was still a bit fuzzy on what exactly he wanted to do once they got there. He cleared his throat. "I'm, um. I'm game if you are."

"Good." Sherlock grabbed his hand before he had a chance to change his mind and led him off across the rugby pitch toward an overgrown path through the forest. John wouldn't have noticed the trailhead if Sherlock hadn't led him unerringly to it, despite the sun having almost disappeared behind the horizon. "This is the most direct way, if not the easiest to navigate."

"I can handle it," John assured him. He was nowhere near as proficient as Sherlock was at moving through the woods silently - Sherlock somehow managed to avoid every stick and dry twig on the ground - but he was in good shape from rugby and at least he wouldn't embarrass himself by needing to ask Sherlock to slow down. They walked in the near-dark for probably fifteen minutes before the trees thinned and suddenly they were facing a stone wall nearly the same height as John.

Sherlock rummaged under a largish fallen log and came up with what turned out to be a dark-colored blanket. He slung it over the wall, then turned and offered John a leg up. "Gate's locked," he said in a low voice, "but the wall can be a bit sharp in places. Up and over - I'll be right behind you."

"God, I feel like a burglar or something." John did put his foot in Sherlock's cupped hands, though, and hauled himself over the wall. Sherlock followed a moment later. He folded up the blanket and tucked it into a plastic bag hidden behind a wooden bench, then led John across the garden and through an unlocked door on the patio.

And holy crap. John had to bite his lip to keep from saying something stupid about the size of the house. Sherlock and Mycroft's family must have been well beyond "rich" and veering into "ridiculously loaded." Even with the lights all off, it was obvious even just the furnishings in the hallway probably cost more than John's entire house.

"Don't," Sherlock murmured. "You can be all astounded once we get upstairs. Mrs. Hudson's the housekeeper, though, and she's got exceptionally good hearing. She thinks I'm in my room working on an experiment."

"You will be," John murmured back. "I promise, you can experiment on me all you like."

Sherlock sucked in a deep breath and quickened his pace. They darted up an imposing staircase, down a second hallway, and into a massive bedroom at the far end.

"Finally." Sherlock grinned at John and shrugged out of his coat. "Her quarters are downstairs, at the other end of the house, so no need to worry about her hearing us. I just don't want her calling Mycroft to come home at once because there's an intruder in the house."

"Mmmm." John shucked his own jacket, then tugged Sherlock over to the four-poster bed which dominated one side of the room. Not what he would have pictured - Sherlock didn't seem like the canopy bed type - but all the furniture looked antique and a modern little twin mattress like John had would have been out of place in the huge room. Plus the rest of the space did scream "Sherlock": bookshelves on every wall, a human skull (!) on the nightstand, glass titration apparatus littering the mahogany desk. John would have bet fifty pounds Sherlock was able to locate every single item in the room simply from memory.

"That's what it's like, is it?" Sherlock breathed. He made no effort to move away from John. "What sort of experiment should this be, then?"

"I think . . ." John traced a single finger down Sherlock's sternum to his stomach, stopping right before he hit Sherlock's navel. "We can't get into too much trouble if we both keep our lower halves clothed, can we?"

Sherlock eyed John's chest greedily. "Does that mean I get to explore your upper half?"

"Depends." John grabbed the hem of his own t-shirt, but didn't pull it off just yet. "You have a hypothesis you want to prove?"

Sherlock licked his lips and nodded.

"Tell me."

"I want to . . ." Sherlock blinked several times, then looked back up and met John's gaze. "Can we start with a thorough temperature analysis of various sections of your skin? Thermoreceptors in the fingertips are incredibly accurate, but those in the mouth and on the tongue are even more sensitive."

Christ. John sucked in a breath, suddenly dizzy with anticipation. "I assume reciprocity would be permitted?"

Sherlock visibly shivered at that, and immediately started unbuttoning his shirt.