Sirius continued to stare, stricken, until Remus's repeated command shook him out of his immobile state. He blinked, and took his hand away from his mouth. "Remus..." he whispered, voice broken and thin. He shakingly took a step forward, lifted a hand but then let it drop. There was no way in hell he could touch him now. If he'd even had that right anymore, he'd forfeited it in the last thirty seconds. "Moony, I--"
Merlin, that look in Remus's eyes. Sirius could count the number of people Remus had ever looked at that way on one hand, and oh god, he'd never imagined he'd be one of them. He'd never thought he'd be the cause of a single drop of blood Moony ever shed.
And here he was. Bleeding at Sirius's hand. And he was afraid of him. Remus was afraid of him.
Sirius was overcome by the sudden urge to vomit. "I'm-- Moony, I--"