JUQ-826 While my wife was on a business trip, I was seduced by my sister-in-law, あず, and we had intense intercourse until all the semen I'd accumulated over 30 days was spent… 天月あず

I work at a trading company and was eating dinner alone again today. My wife and I both work, she's in management, and our lives are work-centric, so we can't spend time together. Sometimes when she comes home, she demands sex intensely to release stress, leaving me exhausted. Seeing this, my sister-in-law Azu often comes over to our house. The conversation naturally turns to marital affairs, and Azu grins mischievously as she teases my crotch. Then she whispers in my ear that if I can hold out for 30 days without ejaculating, I can like her...