Sisters friend pee

[Pissingpeter 21]

Just 10 minutes ago my sister got surprised on her birthday with her best friend coming to town. Her friend is roughly 5'5 slender 19yr brunette wearing an orange crop top with black leggings. She came in the door, talked for a bit and then made a trip for the bathroom after a 4 hour drive. I was sitting in the room adjacent to the bathroom and became immediately aware of what was about to happen. I listened intently and heard her pull her pants down, sit and then start peeing. She peed a light but prominent hiss, wasn't loud and disruptive but it was there and sexy! She actually peed quite a bit, the stream sounded strong for the entirety on the pee. I heard her wipe her pussy and then flush. 

This was an unexpected hot experience, still turned on from it. I am a sucker for a good hiss during a long piss. 

Stay safe everybody! Hope yall get some unexpected pee experiences