Many years ago, I was about ten years old. My mother took me and my aunt go to boutique. I remember that the fitting room was just closed by pulling the clothes.

something like this
At that time, I was sitting on the floor and playing with my toy car. The front is the fitting room. Just when my aunt tried on clothes, I felt the movement in front of me. I looked up and saw that my aunt dint closed tight and leave a gap which can saw 10% of her . At the time, she had already took off clothes and prepared to put on a new one. I saw her wearing an orange color set of bra and panties.

something like this
I immediately hard on but I was scared at the same time, and I realized that my aunt also noticed that I saw it, and she did not care. But I was too scared and didn't dare to look at it. Now think it back and I feel very coward. After the incident, I ask my mom fetch me to her house to find my cousin play, I try to plan if any chance to see her shower or nude but no chance...
ps: This aunt is the youngest, should be 40 years old at that time, is the most beautiful and young aunt. She alway my fantasy target. 😬
Ps: apologise for my bad English