Witnessing her son-in-law's morning erection, what could the widow's mother-in-law be?! (Kanako Narita, KSBJ-385)

My wife, who is pregnant and about to give birth, is in the hospital, so my mother-in-law, Ms. Kanako, will be coming to help out for a few days. Unlike my wife, my mother-in-law's voluptuous figure has always bothered me. We haven't had sex since my wife became pregnant. My stepmother seems to have had no sex life since her husband passed away; I never imagined we'd develop this kind of relationship…