Steve was shivering more than a little, but Tony's arm was warm and heavy and he'd been happy to lean into him. Sometimes being small had its benefits obviously, he was starting to enjoy being tucked under Tony like that. A little body heat went a long way, Steve knew a thing or two about that.
He hadn't meant to scare the other man and he wanted to apologize to him for it. But he couldn't talk, he couldn't even see, his eyes screwed up as the pain intensified. It hurt, it hurt just as badly as it had last time as his muscles ripped and expanded and healed, his bones lengthened and everything adjusted. Steve fell to his knees, crying out again before the transformation was complete once again.
His fingers clenched against the stone and Steve could tell by the size and shape of his knuckles that he was back without even feeling the weight off of his chest as he breathed long and deep. The shirt he wore of Tony's was suddenly too small, the button on the pants torn free and zip busted open and Steve sat back on his heels.