A/N: A companion and prequel of sorts to "Teeth."
Neither beta-read nor Brit-picked.
Sherlock smiles coldly. "Unusually dilated pupils for the brightness of the room, given that you haven't ingested anything interesting today."
"Oh?" John says flatly, unimpressed.
"Obvious."
John sucks in a breath through his nose. "I can see the pulse in your ridiculous cupid's bow. Elevated."
Sherlock presses his lips together.
"Hiding it won't change it," John counters.
"You knew I wouldn't stay clean forever," Sherlock hedges.
John rolls his eyes. "Come off it, you prat; you haven't ingested anything interesting, either."
They watch each other. These rows that aren't quite rows have been happening more and more frequently since Sherlock's return. Nothing this explicit until now.
John steps closer, and Sherlock holds his ground.
Finally, John says, softly but deliberately:
"Oxytocin activates receptors in the nucleus accumbens of the striatum, the same brain area responsible for drug addiction. Drugs merely mimic the high of love."
Sherlock scoffs. "What? John, don't be –"
"You were dead-" He grits his teeth and takes a sharp breath. "You were dead, Sherlock, for eighteen months and three days. Now you aren't. Listen. You don't have to do a damn thing about this - thing." John waves a hand between them, a bit madly. "But don't you pretend it's not bloody there."
Sherlock's bottom lip drops, revealing the rounded arch of his top lip, and John counts the pulse beats, there, on the left side.
Ten. Eleven. Twelve.
Neither of them seem to be breathing.
Thirteen.
"All right, John."
A/N: This started as a 221B, but I had a bit more to say. If you enjoyed it or particularly didn't, please drop me a quick thumbs-up or thumbs-down! Thanks for reading!