Not just pissing, letting out a single drop of pee.
Jack"I still need to piss."
Kayla "Then piss, tf?"
Jack "Nah, I gotta take a singular peepee."
Kayla *Faint wheeze*
Jack *Slightly laughs.*
Kayla "SINGULAR PEEPEE???"
Jack "That's a whole new word right there. Hol up, lemme add that to Urban Dictionary."
(Representation of how this word was born.)