At the hot spring inn we went to for our long-awaited family trip, I ended up sharing a bath with my older sister! Since we're siblings, she didn't bother to hide her body, and her magnificent large breasts were completely exposed, making my heart race! As I washed her back, I couldn't help but get an astonishingly huge erection... Noticing this, my sister gradually became aroused and fiercely grabbed my erect penis, and I couldn't resist sucking and squeezing her oversized breasts that I love so much, even doing paizuri! It was an incredibly pleasurable and secretive naughty experience that I can't tell anyone about!