When you have anal sex with a girl and you suddenly pull it out of her ass and shove it in her vagina...leaving her vagina poop stained.
Oh my gosh kevin the sex was great but...you left me with a poopvagina. I need to go wash
the action a girl commits when she tries to forcably insert a unusually hard log of poop into her vagina causeing it to be there for many days and occasionally many weeks.
"you know how my mom was being such a bitch yesterday? well i discovered it was becuase she was on her first day of poopvagina"