Imagine Bucky's mouth being sore from wearing his mask for too long, and when you get a moment along with him and no one is watching, you slip it off for him to give him a break. As you're standing in front of him, sliding it off, he stretches his sore jaw for a moment then leans in to kiss you. You hesitate to kiss back, whispering "Doesn't that hurt?" He groaned and whispers, "At this point, I really don't care," and leans in for another kiss.