Yubisaki Milk Tea

From Tokyopop: Through a series of coincidences, Yoshinori wound up having to fill in for his beautiful older sister as a model for a bridal gown. Now, he has discovered that he has a liking for cross-dressing, and that by doing so, he is learning a great deal about what it means to be a woman--and a man. Contains a short story entitled "Reason" in volume 2