The brother and sister-in-law living together at my parents' house are troubled by infertility. The two of them, who desperately want a child, have asked me to provide sperm! To think I could do it with my beautiful sister-in-law with my brother's approval! Such an incredibly lucky turn of events brings joy... but then there's my brother's watchful eye during sex! Honestly, I'm disappointed by the mechanical sex where my sperm is the only goal... However, it turns out that my sister-in-law was actually enjoying it a lot more than I thought, and she invited me for an incredibly passionate, unofficial lovemaking session when my brother was away!
