Anonymous: capernoited, bucky's robot arm
He’s so caught up in the glossy slide of Bucky’s fingers that it takes a moment to realize that Bucky’s giggling. He’s got his teeth set against Steve’s shoulder and two hard metal fingers in Steve’s ass, and Steve is so hard, so frustrated, and Bucky is giggling.
"What," Steve asks, breathless.
"I just," Bucky says, then trails off. He presses his cheek to Steve’s shoulder, but he doesn’t stop fingering him, but he also doesn’t stop giggling.
“What,” Steve repeats.
"I just, it’s funny," Bucky says. "They give me this arm, and this is what I do with it."