I ended up staying at my brother's place for a while while studying for my exams, a temporary home-stay arrangement. One night, I accidentally stumbled upon a secret my brother and his wife shared. His wife, on all fours, was grinding her ass against my brother's crotch, her face buried in his lap. I couldn't help but get aroused by the sight and ended up masturbating to it. It seems my brother's wife caught me doing so... "My younger brother-in-law is aroused by me..." she realized. From the next day on, she started showering me with her full attention and desire...
