[Kuromahou Kenkyuujo (Nukaji)] Irika's Tail [head empty]

Cheerful little Irika gleefully teases her older brother by flaunting her brand-new tail plug and asking "Ohh I wonder how it would feel big brother Onii-chan, do you think the worst it gets the better it feels~" before boldly comparing him to a classmate's equipment. As the clumsy sibling dynamic spirals into raw intimacy, she gasps through her first anal experience with wide-eyed wonder, leaving him utterly overwhelmed by her determined, teasing warmth.