Mama to Boku no Karada no Shikumi Okaa-san ni Chitsunai Shasei Shitara Oyakoukou na Sekai / ママとボクのカラダのしくみ お母さんに膣内射精したら親孝行な世界

This is something that is better than lessons to be learned when there is a lot of sperm in this world.
It is normal for a son to do this to his mother, and it is considered filial piety to give mothers as much sperm as possible.
A world where, stretching the skin of the penis, mom says "Please give me baby".
Sexual acts are completely normal in the middle of the city, in schools, in homes.
Sperm donation is carried out for couples who cannot give birth, there are designated places on the train for fertilization,
training programs on "how to impregnate a mother" and "how to kiss her uterus" are broadcast.
This is a story about me and my mother, while we go through the "everyday" in such a world.