At first, I just happened to peek... but my sister's soft-looking breasts, soft peach buttocks, and tight waist... I was tingling at my sister's body, which had matured during puberty, and before I knew it, I had an erection. I was so fascinated by peeking into her bath that I thought I couldn't do it. One day, our eyes met... "I knew you were watching me all this time, big brother." Her devilish side triggered my sexual desire switch, and I was excited by her moist wet hair, the faint smell of shampoo, and her sweaty skin in the summer! Enveloped by a sense of immorality... I licked the lewd body I was peeking at, and we intermingled in a moist, sweaty state as if we were devouring it... Our bodies were so compatible that when my sister let me peek into her bath, it became a signal for forbidden sex...