When you decide you have to shit, sit on the toilet, then mistakenly pee first. When you shit, the weight of the poop splashes the piss (and water) onto your ass and legs.
/ˈkəʊpɛk,ˈkɒpɛk/
noun
An edifice or place dedicated to the service or worship of the Neon Demon where you pay your respects via the acquisition of regalia