My silent and mysterious older girlfriend always unexpectedly reveals herself without a bra, her nipples always showing… (Yuzuki Ria ADN-656)

My girlfriend's older sister is always quiet and reserved, making it hard to tell what she's thinking. So I kind of dislike her. But she's beautiful, and she never wears a bra at home, her nipples are always erect, which looks strangely erotic and becomes part of the fun when I go to her house. I heard that this older sister seems to have had a fight with her casual sex partner and looks very unhappy. I thought it would be great to have such a beautiful casual sex partner… but it seems she's considering me as a potential new casual sex partner…