I was actually thinking...what is Steve and Bucky are not (yet) in a relationship when Bucky asks Steve to "help" him?
Maybe he just literally cannot bring himself to penetrate himself, because it's so upsetting to him, even just with a plug. Or maybe there's a physical reason, like he's temporarily without prosthesis and he hurt his real arm. And he asks Steve to help him out with it. He's very ashamed and humiliated in asking, but hey Steve's a great friend and he's desperate.
What if THEN, while doing it, Steve figures out it turns him on and Bucky finds out he feels more than friendship, but they're both too damn ashamed to admit this and the whole plugging ritual become extremely awkward but also filled with a shitton of sexual tension?
Re: Bucky's wrecked asshole
Maybe he just literally cannot bring himself to penetrate himself, because it's so upsetting to him, even just with a plug. Or maybe there's a physical reason, like he's temporarily without prosthesis and he hurt his real arm. And he asks Steve to help him out with it. He's very ashamed and humiliated in asking, but hey Steve's a great friend and he's desperate.
What if THEN, while doing it, Steve figures out it turns him on and Bucky finds out he feels more than friendship, but they're both too damn ashamed to admit this and the whole plugging ritual become extremely awkward but also filled with a shitton of sexual tension?