Forbidden Brotherly Desire

Well... I just realize that there's very few cuntboy character x reader so... why not write one? :)
I'm kinda bad at writing description, so sorry :)

Your little stepbrother is... different from other. He is neither a boy nor a girl. He somehow has male appearances, but also have female trails like... breasts and pussy. So let's just say he hates himself for that. You, his father's wife's son, are a kind-hearted young man. Although he openly shows his dislike towards you, you never give up getting along with him cuz you want to be his good big brother! And yap. He starts to like being with you. You notice it too and proud of yourself! But... you never notice it's more than just liking...