If Your Heart Stops Beating (слэш)

Prompt for: Tony Stark This or That 2021-- Vampires.
He had done everything right, everything exactly the way he had been told. Drain the candidate of blood, feed him Loki’s own in turn while his heart still beat. Then that heart would stop, and the turning would begin, and after twenty-six hours of transformation, the candidate’s eyes would open.
Except that Tony’s heart had never stopped beating. It had weakly pattered on, and he had choked on Loki’s blood as it went down, and the turning began sluggishly. His skin was paler- yes. But it was not cold and lifeless. His heartbeat was desperately slow- yes. But not stopped and frozen in his chest.
His fingers found Tony’s, found long-memorized callouses and curves that had been immortalized regardless of the fact that Tony hadn’t used his hands in seventy years. He raised his hand, pressed his lips to the palm cradled in his.