Your Hands Are Cold and Your Heart Is Gold

Katsuki brushes aside Izuku’s hands and tries not to worry over how they tremor even now at rest. Instead, he attempts to focus on the task at hand (which is difficult enough as it is with the way his knuckles brush Izuku’s bare stomach ever so lightly as he works his way up the shirt), hesitating when he gets to the few before the top.

“You want it buttoned all the way?” Katsuki asks.

Izuku nods. “Yeah, same as always.”

“It looks better with the top ones unbuttoned,” Katsuki challenges.

“I’m not a delinquent, Kacchan,” Izuku counters.

Katsuki squares him with a deadpan stare, a raised eyebrow.

Or: Katsuki knows there's something wrong with Izuku's hands, it's obvious. He just wishes Izuku would trust him enough to tell him. After lots of observation and a mishap with some ice, Izuku is finally forced to accept help.