The air in the gym was thick with the smell of old sweat, clean leather, and the faint, metallic tang of the weights. A fine dust, chalk and ambition, moted in the slants of afternoon sun cutting through the high windows. Bucky leaned against the rack of dumbbells, arms crossed, watching you. The heavy bag swayed like a pendulum under your half-hearted punches. You were all determination in your posture, but your form was a fucking disaster.

He pushed off the rack, the rubber soles of his boots silent on the mats. “Alright, that’s enough of you just pissing it off.”

You dropped your hands, breathing a little heavily, a stray strand of hair stuck to your damp temple. “I’m trying.”

“I know you are, sweetheart. But trying wrong just builds bad habits.” He came up behind you, and the space around you changed. The air grew charged, the sounds of the gym—the distant whir of a treadmill, the clank of plates—faded into a dull hum. His presence was a physical thing, a warmth at your back that promised both sanctuary and siege.

“Okay,” his voice was a low murmur, right by your ear. “Feet wider. You’re a sapling in a breeze right now.”

He didn’t just tell you. His hands found your hips, his fingers splaying wide. The left, flesh and blood, was warm and calloused. The right, vibranium, was a cool, unyielding pressure through the thin fabric of your leggings. He adjusted your stance with a gentle but undeniable force, turning you, shifting your weight. The touch was clinical and yet anything but. It was an electric claim.

“There,” he breathed, his chest now flush against your back. He was solid, a wall of muscle and history you could lean against. “Now.” His metal arm came around you, the plates glinting in the light. He took your wrist in his hand, guiding your fist into a proper fist, his cool fingers wrapping around your knuckles. “Don’t clench until the last second. You’re not making a wish, you’re throwing a punch.”

He guided your arm forward, a slow, controlled motion. His body moved with yours, a perfect, deadly unison. You could feel the hard line of him against you, every breath he took. His other hand slid from your hip to your stomach, a flat, warm palm pressing to keep you anchored to him.

“Again,” he commanded, his lips brushing the shell of your ear. You threw the punch, his arm guiding the motion. The impact was satisfyingly solid. “Good. Better. But you’re still pulling your shoulder back. You’re afraid of it.”

He released your fist, but only to let his metal hand slide down your arm, a slow, sensuous drag from wrist to bicep, squeezing gently. “This is the engine. Not this.” His human hand slid up from your stomach, over your ribs, to rest just below your collarbone, his thumb stroking the frantic pulse in your throat. “You’re all tense here. Breathe."

You took a shaky breath, leaning back into him. He was surrounding you, his scent—soap, clean cotton, and something uniquely, essentially him—filling your senses.

“I can’t focus when you’re this close,” you whispered, your voice breathy.

A low, dark chuckle vibrated through his chest into your back. “That’s the point, doll. Distraction’s a bitch. You gotta learn to focus through it.” His metal hand came back to your hip, his grip firm, possessive. “Now, again. And this time, put your whole body into it. Don’t think. Just feel it.”