Secret Rites with the Holy Maidens Vol. 1

A sexy isekai story about giving holy maidens a bit of sexual education.

After a late night with an 18+ game, Itsuki wakes up in an entirely different world. He has no interest in being a hero-until a towering, voluptuous goddess appears and assigns him an unexpected mission. To return to his own world, he must guide her devoted disciples in a very different kind of "education." Is this paradise...or a trial he's completely unprepared for?