Riho Fujimori, a young woman about to move into her new home with her boyfriend, has been struggling with a secret part of herself - her ass seems to have a mind of its own, constantly craving anal pleasure. While helping out a sickly college student named Kazuo Ohta, she becomes increasingly attracted to him and eventually gives in to her desires during one of their encounters at his place. As they explore each other's bodies, Riho discovers that Kazuo possesses something special between his legs which leaves her completely satisfied. However, this forbidden relationship threatens both her current relationship status and future plans with her boyfriend.

社会人カップルの里穂と彼氏は、結婚を視野に入れ、新居に越してくる。幸せな生活に期待踊らせる里穂だったが、お尻はもう1つの人格を持っているかのように勝手に動き出すことが悩みの種だった。引っ越し先で苦学生の岡田と知り合う。不健康な岡田の生活を心配し、里穂はテレワークで家にいるので岡田に食事を差し入れしたり面倒を見ることになる。彼氏とのセックスに満足してなかった里穂は岡田の家で昼食を作っている際にお尻が疼いて欲情、そばにいる岡田の肉棒を求めてしまう。※ 配信方法によって収録内容が異なる場合があります。