>>11313362
Granted! You are the twin sister of a princess-- The Princess, in fact, daughter of His Holiness, the Emperor Himself, eternal regent of a thousand-thousand stars in an old, old milky way galaxy. Golden ships wage constant war against the dark in the fringes of the galaxy, earning glory and the right to say they beat back the encroaching blackness and occasional rebellion. Most of this, however, is irrelevant to you and your sister-- except the fact that as eternal as the Emperor is, He has had a lot of time for his genome to evolve within his body and produce something truly new.
You and your sister are the first of a new race; Elflike ears, otherworldly beauty... and strong sexual dimorphism. Once you two started developing, you kept a cool demeanour... and she was hit like a freight train right between the legs. She went from female to full-blooded futanari the instant you two turned 180, and in the 181st year of your lives she still has no idea how to deal with it-- and your old, sweetly innocent habits of sleeping together, nesting with her being the natural big spoon, or bathing together as you washed her thoroughly, or even just the days you used to spend chasing eachother around the palace-ship. You, as the only one who seems to have force of will around here anymore, insist she still join you in all these activities, though you don't know why she's blushing now of all times. Really, the nerve.
(Oh hell, duplicate grants already.