My friend's little sister, Yui-chan, has an amazing figure and lives with her older brother (my friend). She constantly flashes her panties and cleavage without a care, but her behavior hints at deeper, unspoken feelings. When I bring her alcohol as a gift, we end up celebrating her birthday. That night, overwhelmed with gratitude, Yui-chan becomes increasingly affectionate and clingy. Seeing everyone else with boyfriends, she gives me a heartbreakingly lonely look, longing for affection. I can't resist—I pull her close and kiss her. Then I slip off her panties and go down on her, tasting her as she moans uncontrollably. Her intoxicating pleasure tempts me to go all the way, but what awaits us if we cross that line…?