Izuku who runs super damn cold and has almost constant joint pain, so he's snuggled up to one of his space heater boyfriends whenever he can be <3
Shoto is his go-to, especially when in proper pain, cause he can get the other man to adjust his body temperature a bit to his liking. Izuku's favorite position is to sneak under the jacket/hoodie Shoto is wearing and curl up right against Shoto's left side. And if he falls asleep there and ends up too warm, he just rolls over to the other side.
He goes to Katsuki if he's having pain in specific areas, or if he can't get his hands warm no matter how hard he tries. Despite how much Katsuki's will grumble about Izuku being an "annoying, clingy nerd" he'll drop almost anything to warm Izuku up, using his quirk to heat up his hands and massage the tension out of Izuku's shoulders, or just lace Izuku's fingers with his till they feel better.
And if Izuku's whole body just seems to be fighting against him, he'll tuck himself right up against Kirishima. The other man always runs hot, more less cause he's pure damn muscle. Izuku loves to sneak his hands in Kiri's sleeves or under his shirt just to (lovingly) steal some of the other man's warmth. It always makes Kirishima laugh, even if Izuku's cold hands make him jump every damn time. And if Kiri catches Izuku cold he won't think twice before peeling his own shirt or hoodie off and giving it to Izuku <3
