While alone in a small bath with my sister, who is my perfect match, and washing my back, her small, budding breasts repeatedly brushed against mine, giving me a full erection!! But my sister, who wanted to take a bath with me, actually had a purpose! My slightly precocious sister actually wanted to see my penis!! And because of the situation, I realized that my lower body was fully erect!! When my sister saw my erection, she got excited and reached for my dick, saying, "I wanted to see it in a bright place!"...