My older sister, Nene, who is about to get married, has such severe obsessive-compulsive disorder that she can't even kiss her fiancé, Izumi. Worried that their wedding kiss won't go well, she asked her younger brother, Tomoki, to be her practice partner. Will Nene be able to kiss Izumi properly? What about her relationship with Tomoki? Their tongues intertwined, their saliva mixing, their kiss practice gradually turned into something real. Forbidden incestuous NTR sex.