放課後によくゲームをして遊ぶ仲良しグループ。寺橋は美少年の親友・柊もみじからふと香る「女の子の匂い」に気づく。冗談半分で姉の制服を着せてみると、あまりの可愛さに理性が崩壊。発情した寺橋は「ぼくたち、ともだちだよね？」と戸惑うもみじを押し倒してしまう。しかし、もみじは親友の狂った性癖を受け入れ「友達以上」の関係へ…。下着やコスプレ姿で激しく求め合い、男同士の境界線を越えた背徳のねっとりメス堕ちSEX。

A close-knit group of friends who often play games together after school. Terahashi notices a "girly scent" emanating from his handsome best friend, Momiji Hiiragi. Half-jokingly, he tries putting his sister's school uniform on Momiji, and is so overwhelmed by how cute he looks that he loses all self-control. Driven wild, Terahashi pushes down a bewildered Momiji, asking, "We're just friends, right?" However, Momiji accepts his best friend's twisted sexual preferences, and their relationship becomes "more than just friends"… They passionately desire each other in their underwear and cosplay outfits, crossing the boundaries of male friendship in a depraved, sticky, and submissive sexual encounter.