I came to Tokyo to take a qualification exam and ended up staying with my brother and his wife for a while as a temporary homestay student. One night, I peeked at my brother and his wife's secret. My brother's wife buried her face in my brother's lower body and was on all fours, sticking out her ass. I couldn't resist the temptation and masturbated to orgasm while watching the scene, and it seems my brother's wife had found out... "My younger brother-in-law is excited by me..." When my brother's wife realized this, she started pouring all her lust into me from the next day...