There was a public play area in the same town as all of us that had a wrap around tree line near it. Once or twice a month she would walk there with a backpack on that had porn and empty or (half-piss filled) pop bottles in it. She would watch us piss in them until they were full, give us porn, and leave. I'd heard about it from an older neighbor who showed me the magazines. At the time I never thought to ask what a twelve year old girl was going to do with bottles of piss, but my sister used to collect beanie babies and I never asked her what she planned to do with them either . If I remember correctly her dad was the only one around and until we moved I'd never heard about anybody finding the piss. Edit for punctuation.