If she were smart, she would have squatted some where and kept her pants clean
Same sort of thing with me and my cousin. When I was 16 she was 17. She had to go, we'd been eating and drinking some sodas and were walking back to her house. She told me to come around behind a bush with her in a park, I was to "block" anyones view who walked by. Though she insisted I turn to watch. She pulled up her mini skirt (yes it was in the 70s) and squatted down, handing me her panties and I got a great glimpse of her bushy pussy. Holding her panties I saw her pee and poop. I pulled out and peed in front of her after she stood up. I peed all over her pile of poop. I handed her some Kleenex to wipe with, and she just pulled up her skirt presenting a beautiful ass to me and I wiped her clean. I told her I was keeping her panties and she let me.
Eventually we did fuck but that wasn't for a year later when we shared a small apartment at college.