“Takashi-kun, please try to hold back until next month’s hot spring trip.” Those were the words my father-in-law said to me. The thing is, my father-in-law has a backache, and the whole family hasn’t gone on a trip together for a long time, so we’ll take advantage of next month’s few days off to go to the hot springs together. My father-in-law really wants to have grandchildren, and he heard that hot springs are good for “creating babies,” so he made me hold back and accumulate sperm for a whole month! And the day has finally come, and because I’ve been holding back for a whole month, I’m really craving it! But my wife still won’t let me! I can’t sleep, so I walk around to get some fresh air and meet my mother-in-law. My mother-in-law is old but still very beautiful. When I see her going into the bathroom, I immediately follow her. Looking at her curvaceous, sexy body, combined with the arousal from holding back for a whole month, I can’t control myself anymore! I rushed to take over my mother's body and released all the sperm that had accumulated for so long deep inside her! After regaining my composure, I immediately apologized to my mother and left. But the horniness was still there, so I went to my mother's room. Afraid that my father would wake up, my mother pulled me into the bathroom and took the initiative to let me fuck her! It turned out that my father had a backache and hadn't fucked my mother for a long time, and my mother's horniness had accumulated even longer than mine! After understanding each other, the two of us secretly made love throughout the trip. A few months later, my mother called my husband and I and announced that she was pregnant. My wife and father-in-law were very happy, but only my mother and I knew whose baby was in her belly...