original drawn by stmast

Artist's commentary

Original

joint copulation

之前异世界扶她里星云精灵的设定，额外版！雄性与两个阳雌性（扶她）之间进行的繁殖行为！

也就是说，扶她X想要成功受孕，就需要阴道被扶她x注入精液的同时，马眼被雄性Y注入精液。阳雌性除了同事拥有两性特征外，还有一条连接尿道和卵巢的输精管。雄性因为身材很小，一般射精时也不足矣让自己的精液通过长长的尿道和输精管达到卵巢······所以在交配时，需要借助扶她X高潮尿道中填充的精液来流动，才可以保证抵达融合点。在位于融合点时，x的精子会攀附在Y的精子上，随后与X的卵子结合！完成受孕！

这么正经的变态设定到此结束！

That's... slightly confusing because they use Futa X (caps) and x (lower case) as the rather than Z to avoid confusion

But basically, if Z wants to be fertilized, there is the necessity for male Y ejaculate into the urethra of Futa Z at the same time Futa X ejaculate into the vagina of Futa Z.

Apart from having both organs of the sexes, futas also have an extra passage to allow semen to backflow from the urethra into the womb.

But because the males are really tiny, normal ejaculation will not be able to reach the egg, so during intercourse, it becomes a necessity for Futa Z to climax, so Male Y's sperm can ride on Futa Z's semen as it backflows into the passage to the womb, allowing Futa Z to get... fertilized

Why is Futa X even necessary? I mean it's technically self-impregnation at this point because it's the sperm of Futa Z and Male Y

I mean, it would make more sense if it was Futa X that was the target of insemination, as Futa Z has Male Y ejaculate into her urethra, then unloads into X as Z and Y's sperm cells do their thing