Disclaimer: never did and never will own it. Marvel does.
Spoilers: canon until Captain America: Civil War (and the post-credit scenes of Black Panther).
Timeline: supposedly happens between Avengers Infinity War and Avengers 4.
It didn't take long for Bucky to notice that Shuri was running into him on purpose. Regularly, she burst from nowhere at high speed, always ending up bumping into him. He caught her up each time without a fault. Also, each time, he had to restraint himself from hitting her, though lately, as he was twice on his guards for her to do exactly that, he didn't react as badly.
He knew she was not as oblivious as she made herself look like.
"I asked T'Challa to tell you to stay away from me," he said tightly, his left hand thrust deep in his pocket.
"Won't do, Wolfie," she replied airily.
"Shuri," he growled, as they had both stopped with titles long ago.
"Bucky," she said on the same tone.
"I like you."
She mimicked surprise. "Whoa, you like little me? I'm flattered, really–"
"Stop it. Please. I don't want to hurt you."
His voice was soft, almost begging. She turned serious suddenly.
"So you'll hurt in my stand? Wolfie, I mean, Bucky, what I want you to realise is that you won't hurt me. Not now, not ever. You're free from HYDRA." She raised her hand so he would let her continue. "You're free from them because they will never be able to steal your will from you ever again. I understand that you are still not free from what they did to you and made you do. You aren't free from what you are. But you are getting better. You will never be the one you were before HYDRA, you know that as well as I do, but soon, you'll be able to lead a normal life. Until then, I don't want you to be alone and on edge because you fear you'll do something wrong."
"And what if I do? What if something surprises me so much that my reflexes snap in place and I hit someone before I realise they are not enemy? What if I hit you?"
"Then I am an idiot who will regret it very dearly the minute it happens," she said dryly. "Everybody here knows who you were, how you are wired to react. They know how to come to you, not to surprise you. Sometimes, because they're happy for you or because they want to comfort you, they forget and come rashly at you, to hug you generally." Bucky knew she was referring to Steve, who didn't seem willing to understand that hugging him was not as easy as it was before. "But most of the time, they care. In my case, I'm done coddling you."
He bristled at the word 'coddling'. She smiled knowingly.
"You can't live surrounded by people who tread gingerly around you. You'll meet people who will bump into you and not care, who will clap your shoulder before saying something. You lived alone in Bucharest, yet you didn't hurt anyone. People must have crowded you sometimes, no?"
He had a wry smile. "Do you know how much weight I lost during that time because of stress?"
She dismissed it. "You were not eating properly. I will run into you until you understand that you are not a threat to me. This is a calculated risk from my part because I know I have nothing to fear."
He was not as convinced of it as she was, but she didn't mind. She would convince him, in time.