as i know, it is a belief in some european and asian countries.
what i'm thinking is the title came from the (future) seme who is like a walking rabbit's foot.
If you look well, in the first chapter, what seems to be the prologue the uke falls and you can see he has a prosthetic limb (his leg)...that means he lost his leg somehow, maybe the bad seme did I don't know.
But the uke really must bring good luck 'cause the seme has been having really good luck since he met him
sharp eye bro
i was so curious abt the title so i researched some stuff and according to the article carrying or possessing a rabbit's foot is supposed to bring you good luck. the traditional way to get a rabbit's foot so it's legitimately lucky is to kill or amputate the rabbit on a grave. the evil the person on the grave is, the luckier it is.
im still not sure how this is representing the story but because there are certain elements that are somehow the same even tho it's not chronological, it seems like the author got inspired because of the lore. i guess it's also kind of a foreshadow for those who knows the lore?
im just sharing just in case someone else is wondering and is too lazy to look it up themselves.