I ended up living with my sister-in-law for a week. My sister-in-law, who is strict with me in front of my brother-in-law, starts touching my penis while being sweet and flirty the moment my brother-in-law leaves. She knows I'm watching and deliberately shows me sex with my brother-in-law, making my penis rock hard. I can't hold back and masturbate, only for her to suddenly appear and force me to have sex with her, leaving me exhausted every day. On the eve of my departure, I enjoyed a soundless sex and a sweet cohabitation life next to my drunken brother-in-law!