Yea is really little so he copies his dads and how they call each other. Plus if u look back to Ch. 39 when Yua is an egg Seme calls Uke a mom and he says to not call him that. So they probably won’t be calling each other that.
I hope this answers this a bit. But it never fully states anything.
Thank you for all the translator notes! I always appreciate them!!! Give us so much for context and meaning behind everything
They are useful but this translation is stolen, the person who translated this only uploads on Tumblr and Mangadex