Pee. I had a pee fetish before I even knew how to masturbate. I was about 12 when I started reading a lot of stories about people peeing their pants. I was so interested in it, eventually I started holding in my pee until I wet myself instead of using the bathroom whenever I thought it was safe. I remember I would have an erection throughout the whole process, eventually I had to stop peeing my pants because the smell was soaking into my chair and it started smelling really bad so I stopped, the cleanup is also a huge pain . I remember googling how to remove pee smell from chair and I eventually found some guy saying that vinegar got rid of the smell. So I poured some vinegar on my chair and it just smelt like vinegar until the vinegar smell went away after 3 days and then it didn't smell like pee anymore.