Sherlock treated waking up like he did everything else: he analyzed it.
Before his eyes even opened, he was already observing. The familiar scents of resin, lemon cleanser, and just a touch of sulfur greeted his nose, and the silky smoothness of expensive sheets pressed against his bare back confirmed that he was indeed lying in his own bed. When his eyelids did flick back and adjust to the dim light of the room (apparently it was roughly noon, judging from the amount of light that snuck between the cracks in the curtains), his eyes traced over the well-known bumps and ridges on his bedroom ceiling before briefly flickering over the patterned paper on his wall.
And of course, he noted that his right arm was asleep, from which he easily deduced that there was something putting pressure on it. Tilting his head, he got an eyeful of the cause of his limb's pins and needles: Dr. John Watson.
The good doctor was sprawled out next to him, his head resting on Sherlock's pale bicep. His hair was mussed, and he was naked to the waist down, where a sheet just barely covered the junction of his hips, much to Sherlock's displeasure. However, he pacified himself easily enough with the fact that, if he so chose, he could yank away that sheet and drink in the bare glory of the veteran doctor that was John Watson. That was his.
A self-satisfied (and somewhat smug) smirk played across his thin lips as he reminded himself that if he leaned over and swiped his tongue over one of John's simply succulent clavicles, he would taste their combined sweat, a surprisingly heady taste.
Just the thought of that particularly powerful aphrodisiac was enough to whet his appetite, and he leaned over and pressed his mouth to John's exposed neck, nibbling and nipping, before smoothing everything over with a lap of his tongue.
His doctor woke with a sleepy groan of confusion, though it quickly turned into a full-out moan when Sherlock's hand meandered down to give a friendly 'hello' to his morning wood.
Watching as his doctor's face become flooded with those beautifully unbridled emotions of his, Sherlock smiled, and with a final suck at the impressive hickey that John would have no hopes of covering up (Sherlock could imagine the exact shade of puce that Lestrade would turn when he laid eyes on it) he pulled away and set about doing the wonderfully pleasant task of getting the good doctor off.
Minutes later, and Sherlock basked in the fascinating riptide of pleasure on John's face, putting each facial movement and flicker of the eyes down to memory. As John slowly floated back to earth, Sherlock pulled him close, nestling John's head against his neck so that his hot, panting breath was blowing against Sherlock's chest, sending a delightful shiver zigzagging up and down the world's only consulting detective's spine. The overall effect was simply lovely, and he lazily traced geometric impossibilities onto muscled flesh until John finally spoke.
"And a good morning to you too, Mr. Holmes," John whispered, his voice still a touch breathless but noticeably sarcastic, even as one of his hands unconsciously (but far from unwelcomingly) came to rest against Sherlock's chest, his fingers dusting over pale skin like a kiss, causing Sherlock's eyes to flutter closed for just a moment.
They lay there for a few minutes, silently relaxing against each other as their hands languidly brushed over collarbones and sensitive sides, before John suddenly pulled back a bit so that their eyes met. Sherlock's eyebrows moved up a bit at the out-of-place mischief that glittered in the doctor's eyes, and he was just opening up his mouth to inquire about the odd behavior when John's hand, which had apparently snuck underneath the sheet at some point, traced a ghostly figure eight on one of his inner thighs.
As his consulting detective's eyelids jerked closed at the erotic sensation, a grin broke out on John Watson's face as he leaned up and placed a line of soft kisses along Sherlock's jaw, his hand drifting up so that he could return the favor.
Neither of them got out of bed until dinner.