I've always been turned on by the female form since I was little. This was also the time when I started to masturbate.
The first time I ever saw a girl's private parts was when I was about 9 or 10. I was at an uncle's house and I had to go to the restroom. One of my female cousins, who was about 13 or 14, was in there. I knocked on the door and she said come in. I guess she must have thought I was someone else like her mom. Anyway, I opened the door and walked in and she was facing me. She had just finished peeing and was pulling up her panties and jeans. Her panties and jeans were about mid-thigh when I saw her. When she saw me, she looked kind of shocked and lowered her head by bending at the waist to cover her private parts. She had long black hair so by doing this, she was able to keep me from seeing her privates until she pulled them up. This was one of my earliest memories of getting an erection and masturbating.
Another time when I got a hard on was when I was at my aunt's house. She was about 24 at the time. Anyway, we were very close. My aunt was very pretty and had a great body. One thing she would do was grab my butt, saying I had a big butt. This was harmless since she was just teasing me. One time, she was getting ready to take a shower so she had a light blue cotton robe on that was very short. On her way to the bathroom, she ran into me in the hall and grabbed my butt again teasing me as usual. But this time, I did the same and grabbed her butt over the robe. The robe was made of a thin type of cotton and I couldn't help thinking how smooth her butt felt. Then I asked her, curiously, if she was wearing underwear and she said no. I was only about 11 or so but this gave me a big erection since I was actually touching a grown woman's butt through the robe and she wasn't wearing underwear.
Another thing that turns me on is when a woman loses her top, accidentally. I'm not sure why this turns me on but it does. I guess its cause they dont intend for you to see their boobs, but you still see them. However, I usually only get turned on if they are attractive. A couple of years ago, I was watching a mexican tv show and they showed a clip where this happened to a famous singer in a South American tv show. She was in her early 20's, had light brown hair, and a great body. She was right in the middle of singing and dancing when her halter top strap broke around her neck and fell. She was able to catch it around her stomach area but not before exposing her breasts. When this happened, she quickly turned around and ran off the stage embarrassed. The host of the show came to her backstage and gave her the coat she was wearing. Then she came back and finished the song. When I saw this, I got such a huge hard on that I had to masturbate right away. In the days that followed, I couldn't get this image of her top falling off because it turned me on so much, especially since she was a very beautiful woman. I was masturbating constantly because of this. She appeared on the show several days later saying she didnt take the incident seriously since accidents do happen, which is true.
I have many more stories but I'll save those for later.