My brother's wife's busty big breasts - Unlawful family incest - only the husband knows about it -

Rui-san (Aiki) married my older brother, who lived in a male-dominated household. Although she is a bit overzealous in helping my brother improve his energy, she is a cheerful and good-natured person who treats me and my father-in-law, Yoshisuke, kindly. She obeys her older brother's orders when he goes on a business trip, and she eagerly takes care of her father-in-law, who has injured his back, while swaying her huge breasts. One day, I caught Rui taking a shower, and I couldn't contain my excitement and came up with a plan...