A fancy way to say the number 22, which happens to be my favorite number. *Note... Twatteen is an acceptable alternate spelling especially if you want to kick in a little extra twat.
a wombo (word combo) of the words rotten and twat, meaning a smelly vagina. Adjective used to describe the girl's vagina or a girl herself with a rude demeanor.
Ex 1:
guy 1: hey man, how'd your date go last night?
guy2: pretty good, up until I went down on her. That bitch was Twatten!