Ano Ko no Kawari ni Suki na Dake – Episode 1 (ES)

In this first part of the OVA, Akio, a polite, muscular former rugby player, is married to the pregnant Reina. With Reina temporarily out, her mother Minako (Akio's mother-in-law) is helping around the house. While browsing old clothes, Minako tries on revealing outfits—including skimpy lingerie, string panties, and a cheerleader uniform she finds. Mistaking her for his wife from behind due to the outfit and similar build, Akio suddenly embraces her from behind, driven by over a month of sexual frustration.

He quickly realizes it's Minako and pulls back in shock, confessing his pent-up agony and near-breaking point of abstinence. Moved by his desperation—and perhaps her own suppressed desires—Minako gently proposes, "What if I become her substitute for you?" What starts as a compassionate offer soon ignites an intense, forbidden encounter. As they give in repeatedly, Minako's nurturing maternal instincts warp into raw, animalistic femininity. She eagerly takes every accumulated load, crossing boundaries she may never recross. By the end, the once-proper mother-in-law fears she can no longer return to her former role—her body and mind forever changed by the pleasure of being used "as much as he wants."