AMBI-130 Brother-Sister Complex When the Sister Got a Boyfriend Yuisei Yui

"A guy who looks at his sister with sexual eyes is a strange guy," I thought. Until her sister has a boyfriend... I don't care what her sister is doing, and I'd rather have less conversations and more contact with her. It was such a sense of distance from her sister. But when she hears her boyfriend's phone call and finds her cute underwear that she didn't have before, she realizes that a different feeling is starting to grow inside me...