ERDM-171 - "Promise me it'll only be once..." I had sex with my wife's erotic mother in her fifties... 4 hours of immoral relationship

My wife was hospitalized due to difficult childbirth, and my mother-in-law was worried and came to Tokyo from the countryside. The son-in-law is happy that his mother-in-law has come all the way, but he actually has ulterior motives for her... One night, he promises to have sex with his stepmother just once. Living with my mother-in-law for a while...something happens! ?