Sister Hole

The protagonist's ejaculation was being controlled by his younger sister, who is beautiful, intelligent, and well-behaved, and even has fans at other schools!? Jealous that he was talking to a female senior, she tortured his nipples, removed his chastity belt as he begged, and performed fellatio on him♪ I can't get enough of the sight of the younger sister, riding on top and taking her brother's virginity, thrusting her hips with a look of pure ecstasy on her face, begging him to ejaculate inside her vagina.

Source: Melonbooks, translated