Please create a fictional, comedic and vividly detailed Z Nation story about 10K and Citizen Z on a scavenging run. After they finish the run, 10K finds an outdoor shower and decides to use it, he tosses away his clothes until he's in the buff and bathes under the showerhead (describe his physique and butt), describe Citizen Z's reaction as 10K's butt jiggles as he shivers from the water being cold at first, then turns to face Citizen Z while scrubbing his armpits, Citizen Z seeing the front of him. Add dialogue throughout the story