HUNTA-982 "Let's take a bath together, big brother!" A hidden huge bust... no, it's not hidden at all, it's ridiculously huge. My little sister and I are in the narrow bathtub alone, and if I get a full erection...

Even though my little sister has become a schoolgirl, she still wants to take baths with me, which is troublesome! Because I like her… Naturally, since I'm concerned about my sister's chest, I strongly refuse to go in. But she's so insistent that I can't refuse, and when the two of us enter the narrow bathtub, her breasts, which are much larger than expected, keep my eyes glued to them! Moreover, because the bath is narrow, my sister's breasts keep hitting my arms! If they keep hitting, of course I get a full erection! If I'm erect, my sister will find out…