Early in the morning, when everyone was asleep, I was about to take a bath when my cousin, who had been staying over since the previous day, started taking off her clothes and said, "Let's take a bath together!" I couldn't help but get an erection at the sight of her grown-up breasts and plump ass. She pressed her plump ass against my dick and said, "You're not thinking about anything naughty, are you?" As we washed each other, she grabbed my erect dick and we couldn't stop getting excited, so we started touching each other instead of washing each other. Her grown-up body and her wet slit were not enough with my fingers, so I inserted my dick. We had sex secretly in the bathroom.