Sherlock tastes blood.
His tape-wrapped hands fly up to block the next blow, right hook, predictable, thrown with the wobbly force of a sack of flour. The punch collides with the wall of Sherlock’s forearms; its owner stumbles forward. Simple physics: an object in motion tends to stay in motion. Fighting is only physics. Every motion must be controlled.
Sherlock waits for an opening, a slow-motion tick of seconds, a shoulder dropped, a hip off-balance. There it is, like the click of a camera’s shutter: the point.
His fist flies out and strikes at the juncture of jaw and neck. Arms go limp, legs stagger and collapse, a sack of flour hitting the ground in a puff of dust.
Sherlock steps back, wings of adrenaline beating in his chest, and pushes a sweaty lock of hair from his forehead. The world pulses in dim cheers and bright light.
* * *
If John was home, John might see the bruises that bloom under Sherlock’s skin, pools of yellow and purple, broken blue veins, red abrasions, a road map of Sherlock's reckless choices. John would clench his jaw, and he'd apply salve with warm fingers, raising gooseflesh over Sherlock’s arms.
When John noticed the gooseflesh, utterly out of Sherlock’s control, he’d laugh. Not aloud; no, he’d be angry with Sherlock, the set of his jaw calculated to make Sherlock regret any future stupidity or rash decisions. But John’s eyes would laugh. And he’d duck his head and hide his expression, and both of them would know that there are things beyond anyone’s control, things that just happen. Sherlock can’t help the gooseflesh, just like he can’t help the way his heart kicks when John’s hands touch him.
John, for his part, can’t help fixing Sherlock. He can’t help finding him, healing him. John will pull his gun and save Sherlock’s life over and over again. And then he’ll round on Sherlock, snarling with worry and annoyance, and his eyes will laugh despite it all. Yes. Again. Let’s do it again.
John’s not here to see these bruises.
But the dull ache of a bruise feels like the ghost of John’s hands, so Sherlock goes to the ring.
* * *
He knows it’s reckless. With one unlucky punch, he could be seriously hurt. Sherlock has to be faster than anyone. He has to be stronger. And he is, so far.
It should count for something. Sherlock keeps waiting for it to be important: his strength, his speed. He can solve these men like cases, pick them apart with well-placed blows. He picks them apart, and victory arrives with an empty rush.
John would lose his mind, if he knew. John would tear down the flat.
John doesn’t know, so Sherlock tapes his knuckles.