“Steve, come here.” Tony’s voice was soft, but Steve hopped to his feet and crossed the room to where Tony sat at his workbench. The surface was littered with delicate tools and scraps of metal. Tony held pliers in one hand and a delicate circle of metal in the other. He didn’t acknowledge Steve’s arrival, beyond lowering his voice further. “Do you trust me?”
“Of course,” Steve replied, trying and failing to keep the hitch out of his voice.
“I need you.” Tony twisted the pliers one last time, then smiled. “To do something for me.”
Steve nodded. He didn’t trust his voice. He wasn’t sure he could trust his knees not to give out.
Tony pulled his t-shirt off, revealing smooth skin wrapped around tight muscle, and the web of scars that surrounded the arc reactor. Steve wanted to reach out and touch, but he wouldn’t. He wouldn’t touch, or move, or act until Tony told him to.
Tony's manic mouth started to move a mile a minute drawing Steve's gaze back up. “I had this thought, I honestly don’t know how I didn’t have it before, but it’s all I need to fix the cycling issue and even, dare I say, stop that pesky little short that happens if I go for a run and then touch metal while simultaneously running the microwave.” Tony tipped his chair back and tapped the fingers of one hand on the arc reactor, while the other held up the carefully shaped ring from the workbench. “Just a small addition to the casing. It’s genius, if I do say so myself, which I do, almost daily.”
Steve worried at his lip, wondering if he had imagined the growing tension from earlier, until Tony settled back into his chair, monologue over, and held Steve’s gaze in silence for a moment. “I need you to do exactly as I tell you.”
He was beautiful and serious and commanding and Steve’s stomach swooped as the rest of the world fell away to leave only Tony in sharp focus. The tension returned, tenfold, all wound through Steve’s nerves until it pulled him taut.
“Yes, Tony,” he replied, automatically, and then blushed as he realized how that sounded.
“Good.” Tony pressed the release and the arc reactor popped forward. “Take it out.”
The reactor was heavier than Steve expected. A thick, braided cable ran from its base into the casing cut deep in Tony’s chest. Steve cradled the device, intensely aware of the power he held in his hands. His heart pounded so loudly he was sure Tony could hear it. He wanted Tony to hear and know the effect he had on him.
Tony kept his hands on the armrests and directed Steve with only his voice - steady, sure, firm. Steve followed his instructions in a haze, his entire mind absorbed by his task. There was no workshop, no Avengers, no Captain America. He did as Tony told him and it was so easy.
With Tony’s guidance Steve teased apart the tiny pieces of the arc reactor and inserted the new piece, clicking it into place behind the vibranium housing.
“Good job, Steve,” Tony whispered, his smile playing at the edges between pleased, proud and dirty. The praise shot straight to Steve’s core and he sucked in a slow breath, keeping his hands steady as he snapped the device back into one piece.
Steve pressed the reactor back into its casing with a satisfying click. He let his palm rest over it, the blue light dancing through his spread fingers.
He was so absorbed in the reactor’s glow that when Tony’s hand slid to Steve’s hip he startled. The hand stilled and so did Steve, willing it to stay. Then it moved, sliding upwards until it could wrap around the fabric of Steve’s shirt and draw him close enough for the other hand to join it.
Tony walked his hands up Steve’s chest, grabbing alternating fistfuls of t-shirt and sending Steve’s clothes into disarray, as he climbed steadily higher. Steve leaned into the pressure, feeling the searing heat of Tony’s bare chest against the now exposed skin of his stomach.
Tony paused, hands clenched in the fabric over Steve’s heart, their faces only inches apart. His eyes flicked down to Steve’s mouth. Tony didn’t demand, not this time. Instead, he tipped his gaze back up to meet Steve’s and asked, “May I?”
The “yes” tumbled out against Tony’s lips as Steve surged forward.