I was 15 years old when this happened. I went to this park with my mother, her 2 female friends and their two 11 and 12 year old daughters. We had been to this park many times before and it wasn't too busy but there were always some people around. The park was more of a forest but had a small beach which was used by some for swimming. I was going to be swimming as were the two daughters. The daughters were getting a little playful with me and tried to pull my swimsuit down a few times. I was getting a little annoyed as they managed to expose my ass a few times. Once they caught me off-guard and managed to pull my swimsuit down below my knees exposing my ass and penis. No one was near us when this happened which was good for me. I pulled my swimsuit up and then grabbed their bikini tops and pulled them down to expose what little breasts they had. The girls screamed which had our mothers come over to see what was going on. They came over to see the daughters tops down and asked why. The daughters told them I did it and my mother started getting very angry with me and told me I should know not to do that. I told her the girls had pulled my swimsuit down exposing me and all she said it was it was not an excuse to do it back to them. We argued for a bit until she told me she wanted them off. She was serious and the next thing I am doing is handing her my swimsuit. I am standing there naked and all she said after that was that I no longer needed to worry about the girls pulling them down. She told me to go play and I kept mentioning I was naked and everyone would see me. She told me I got myself into this and it was my problem. Once again she said to go play but she said it in such a way that I knew she meant it and I better do it or else. I spent the next few hours literally naked and being seen by more than a dozen or so people and all because two girls pulled my swimsuit down and I retaliated once.