Usually used when describing a child who's only topic of conversation is of a sexual nature, ie the genitals , sex and milf spotting. A common insult for most teenagers, used instead of dickhead a form of jennan but used in a more sexual manner. The most common jennantalia will name theirs or close friends sexual anatomys and there phone will be loaded with cheesy, awful songs such as 'the ladies bras' and 'show me your genitals'
Friends who can critique eachothers genatalia in a completely asexual way. Genatalia buddies can be either of the same or opposite sexes. When one's genatalia is being obseved by their partner, traditon says that the one being observed must be in the position of Michelangelo's David, while the one observing must be in the position of Auguste Rodin's The Thinker.
"Well Susy, your vagina is a bright shade of pink that is quite inviting. Unfortunately, your labia is quite small. Furthurmore you seem to be in a perpetual state of camel toe, this not a bad thing, yet not a good thing. Overall, your vagina is rather pleasing."
"Oh thank you Pat! We are truly a great pair genatalia buddies!"