Steve smiled gently. Bucky was so nervous, it was refreshing in a way to see him caught off guard like this. James Barnes had always radiated confidence. This was sweet.
"If you asked Peggy, I'm sure she would be willing to help. Or I can ask her, if you prefer." He arched a brow. "Honestly, Buck, I doubt she knows marriage tradition enough to even consider you might be shopping for a ring for her. You might be able to get away with taking her out yourself, getting her opinion, and then buying the one that makes her light up. You could ask her then, or go back and buy it later. I didn't read anything about rings with mermaid marriages." He tried to remember if there was anything specific about mermaid traditions that Bucky might find useful.