"-ond derivative so I could investigate your concavities."

A startled little snort of laughter from behind drew everyone's attention to the door, halting Natasha's half formed retort. Bruce was leaning stiffly against the doorjamb, hair dusty and messy with streaks of mud on his forehead and jaw. The skin around his eyes was tight with barely suppressed pain.

"Back so soon Hulkie pie?" Tony grinned and handed Clint his drink, moving to pour a glass of wine for the new arrival.

Pink bled across Bruce's cheekbones, obviously embarrassed, and Steve and Natasha turned as one to glare at Tony, but it was less because of his words and more because of the thick rumble from the Other Guy that felt more like a contented purr than the start of an angry roar. His lips were twisted down into a small frown, but his eyes were still bright. "Hulkie pie?"

"Would you prefer Brucey Wucey? El Hulkorino? Uaine, ohonte, gwyrdd?"

"Shall I call you Stainless Steel then? Or Tin Foil? Whero, sarkans, coch, lāl?"

Tony gave a delighted cackle, starting towards Bruce with their drinks in hand. "Touché, my friend."

"You were perfectly capable of calling me Bruce or Dr. Banner earlier, why the sudden aphasia?" Bruce cocked his head, taking the wine glass as it was held out to him. He dragged a fingertip over its rim, curling his pinkie low about the stem. He spun it slightly, eyes following the play of light in the small whirlpool at its centre and completely missing the way Tony's eyes darkened.

"That was before I saw you naked. Your body is almost as sexy as your brain." Tony grinned and winked, a filthy, flirty little thing that made Bruce choke on his next inhale. He ducked his head, flushing darker as he felt another purr from the Other Guy tremble through him. He glanced across the vast expanse of the sitting room. The others were all very pointedly turned away from them, but Pepper and Thor couldn't keep the knowing, almost giddy smiles off their faces.

"Hm. Ah, thank you?"

"You are. Gorgeous, really. I'm attracted to you like the Earth is attracted to the Sun; with-"

"-a large force inversely proportional to the distance squared?"

"You're perfect. Be my science boyfriend?"

"I prefer the term science life partner."

"Wanna couple our equations tonight?"

"We fit together like the sticky ends of recombinant DNA."

"Oh Dr. Banner, you sweet talker you! I feel so special."

"You're more special than relativity. Seriously though, I do-"

"It is a good idea. A very good idea. According to the second law of thermodynamics, you're supposed to share your hotness with me. So. You free tonight? I know this great little Italian restaurant, you'll love it."

"If it's actually in Italy you should just call it a restaurant."

"You know me too well, tesoro mio."

"Not well enough, cariño."

-w-w-w-w-w-w-w-

Sorry about all the language kink and the way it degenerates into dialogue at the end. Ohonte, gwyrdd and uaine are the Mohawk, Welsh and Scottish Gaelic words for green. Sarkans, whero, coch and lāl are the Latvian, Maori, Welsh and Hindi words for red. Tesoro mio is Italian for my darling (lit. my treasure). Cariño is Spanish for sweetheart.

(Correct me if I'm wrong. Please.)