This drabble comes before the consummation of the relations between Sherlock and John... but John gets his top off and we go through the process of Sherlock getting turned on : ) Ask me or search online for any vocabulary queries : ) All italics = Sherlock's thoughts.
Muscles
"John, your phone's ringing. It's your sister and she hasn't stopped since nine-" it was now ten- "and the inanity of the ringtone is killing braincells." Sherlock strode to John's room with the vibrating phone held in front of him like one might hold a pirahna under water. He got to the door and, remembering John's recent tirade on knocking, tapped three times.
The third tap just so happened to knock the door open from being tightly closed.
"Joh-" Sherlock froze as John finished a sit-up. Torso toned, back broad, skin sweaty and glowing from the light and wind blowing from the open window, where thin, white cotton curtains billow. The cool air had alerted John's nipples and, feeling a tad inebriated, Sherlock's pupils dilated as he was sidetracked by that chest... It must be noted here that Sherlock had all of three seconds to compute the following until John stood to attention.
Matured pectoralis major, further defined by exercised pectoralis minor; Trapezius raised; Latissimus Dorsi toned, robust... Here, Sherlock experienced the internal shiver accompanied with such a thought as employing the eight intrinsic and extrinsic muscles of his tongue over that 'toned, robust' territory of army-boy flesh. An influx of defiantly subjective words plowed to the forefront as he studied John further.
Ripped, hulky, brawny. Compact. This was a voice Sherlock was not accustomed to and it sparked his entire nervous system like dynamite. His IQ practically licked its lips as if bored with nutrition and drooling for steak, imagining the sensation it would cause both parties if Sherlock somehow stimulated the lateral and medial pectoral nerves... No! Concentrate. Be objective.
Faint scar on right shoulderblade. Recently shaved hair at nape of... Sherlock shook his head. Nape of neck. Fine, not working. Look somewhere else. Army-camouflage trousers. His eyes. Focused... determined... exhalation from mouth sure and- External oblique, internal oblique, rectus abdominis, transverse abdominis- hard not to contemplate raking unguis over thoraco-abdominal nerves.
Sherlock gritted his teeth and unclenched his hands. The vibrating phone did nothing to help. Experiencing xerostomia. He actually felt his ears burn as John stood up.
"Oh, thanks-" John paused as he caught sight of Sherlock's glazed-eyed expression, his lips slightly parted.
Suddenly, Sherlock swallowed, exhaled, turned on his heel and strode back to the living room, phone still in hand. John followed, barefoot.
"Sherlock?" When John got to the living room, he found the mobile still buzzing, on the table and flipped it open just as the front door banged shut. "Hello?" John spoke into the phone.
"John! How are you? I've been calling for an hour! Are you okay?"
John cleared his throat and pulled a hand around the back of his neck.
"Yeah, I... I think so."