The Labyrinth of Milking / 搾精の迷宮

Deep in a remote cavern, the labyrinth's chalice lies, and it's said that if one fills it with magical power, one gains immense magical power. The magic within the labyrinth operates according to a special law: the stronger the futanari penis, the more powerful the spell, and the larger the breasts, the more spells one can cast. Magic resides in sexual function. In other words, filling the chalice with magical power means continually offering futanari semen to it. Filling this enormous chalice with semen is no ordinary feat, but exploring the labyrinth will help to make your futanari penis stronger and more robust, and your breasts, too. But beware: the monsters in the labyrinth will relentlessly try to make your futanari penis ejaculate. Futanari semen must be offered directly to the chalice. Explorers who take on the Grail must explore the labyrinth, hone their futanari dicks and magic, slay monster girls, and jerk off their futanari dicks in front of the Grail.