"Takashi-kun, please try to restrain yourself until next month's hot spring trip." Those are the words that my father-in-law said to me. The thing is that my father-in-law has back pain, the whole family has not traveled together for a long time, so on the occasion of a few days off next month, the whole family will go to the hot springs together. My father-in-law really wanted to have a grandchild, I heard that hot springs are very good for "creating babies", so he forced me to restrain and accumulate sperm for a whole month! And this day has come, because I have endured for a whole month, I have been craving it so much! But the wife still refuses to ask for it! Uncomfortable and unable to sleep, I walked around to breathe the air when I met my mother-in-law. My mother-in-law, despite her age, is still extremely beautiful. When I saw my mother go into the bathroom, I immediately followed her. Watching my mother's full, erotic body, plus the fever because of restraint for a whole month made me unable to control myself anymore! I rushed to take over my mother's body and discharged all the sperm that had accumulated for a long time into the depths of my mother's interior! After I regained my composure, I immediately apologized to my mother and left. But the heat was still there, I went to my mother's room again, afraid that my father would wake up, so my mother dragged me to the bathroom and took the initiative to let me fuck! It turned out that because my father had back pain, he hadn't fucked my mother for a long time, and my mother's heat accumulated even longer than mine! After understanding each other, the two constantly secretly made love during the trip. A few months later, my mother called my wife and I and announced that I was pregnant. My wife and my father-in-law are very happy, but only my mother and I know whose child the baby in my womb is...