In theory, Steve knew how bras worked - but Rogue was right in thinking he'd never actually taken one off someone before. He certainly wouldn't be able to do it without looking, and they'd already established that she was more comfortable if he just ignored anything having to do with her back. And that was fine. It definitely wasn't her back he was focused on at the moment.

Watching her arms move back, the bra now unclasped and nothing holding it on except pressure from her arms and its own shape - Steve wasn't quite sure what he was feeling (besides lust - he was definitely feeling lust); anticipation, and maybe the best kind of nerves, like just after he'd jumped out of the plane over enemy territory, with nothing but a fake shield to aid him.

Standing up, he wrapped an arm around her so she wouldn't stumble back from the sudden proximity. He reached up and pulled on the strap of her bra, moving back just far enough that he could tug it down her arms.