I work at a publishing company and live alone in a large house. My wife is often away on business, and when she returns, she demands sex frequently, leaving me exhausted. Knowing this or not, my sister-in-law, erika, often comes to visit. That day, after chatting about daily life, we started talking about nightlife. With a mischievous expression, erika touched my crotch. Losing my reason, I tried to take her body, and erika whispered, if you can abstain for 30 days, you can do whatever you want to me...