I ended up living with my sister-in-law's brother for a week. While my brother-in-law was out, my strict older sister suddenly became affectionate, touching my cock. She acts tough in front of him, but when he's gone, she gets all lovey-dovey—making my dick rock hard. She deliberately lets me see her having sex with my brother, and when I can't hold back and start jerking off, she suddenly shows up and forces me into sex. Every day becomes unbearable. On the night before I leave, she has sex with me right next to her drunk, sleeping brother, making me moan quietly as we mess around. My days of indulging in this cohabitation continue.