A WeeWee Girl is a younger sibling that tends to annoy you. They are usually under the age of five years old and unpotty trained, often relying on their older sibling to help them go wee wee. Your younger sibling may only be referred to as a WeeWee Girl if you are ginger and/or obese.
Ginger Person: "My little sister is so annoying"
Cool Person: "Your sister must be a WeeWee Girl"
on Wednesday where women are to give off big dick energy
Yo dude Cindy is acting so masculine today
Must be weewee girl wednesday