Usagi has always had an odd interest in pee ever since she was little. It wasn't anything sexual, it was just she found it much more fun to use the bathroom to pee anywhere besides a toilet. Since her dad is at work most of the time, and her mom never pays much attention to where she is, she often is able to go to a park a couple blocks away from her house in the outskirts of her area. This was one of her favorite places to pee.
It was a very secluded park that she hardly ever saw anyone at. There was also a very large nature trail behind it, that she could navigate with ease, so if someone was at the park she could go there. At the park she explored every spot imaginable. She would pee under the climbing hill, pee down the slide, or even pee against a tree (she was fully able to pee standing up and even semi-controling the aim of the stream). She would do this on a regular basis sometimes going several days in a row and sometimes going once or twice a week.
She never told anyone about her secret, not even her best friend Naru, who once asked why she's not around sometimes when she comes to visit. She really wished she had someone to share this hidden fetish with her, but she was too shy someone would think she's weird for it.
It got harder when at 14, she got a cat named Luna who was actually her talking guardian from the Moon Kingdom. Luna was often clingy when she wasn't roaming the streets, or after the other sailor scouts came along, discussing strategy with Artemis and the other scouts. Even after the sailor scouts arrived she would always question where she was going and often go along. Sometimes she was able to escape Luna by saying she was going to hang out with Naru, and come back saying she wasn't home, but it was a lot of effort. Another nuisance was as she grew more attached to her friends, they had more sailor meetings and they wanted to hang out with her more. This caused her to lose a big portion of her free time, but she would still rarely go out and pee at the park on weekends.
She was very, very, tempted to spit it out a couple times when she was alone with one of the sailors, but she could never bring herself to do it. She felt they would think she was weird and not want to be her friend anymore. However, little did she know they would eventually find out on her secret.
