fanny fart vs vaginal flatulence

fanny fart

noun

  • An emission of air from the vagina, especially when audible. 

  • A (normal) fart. 

vaginal flatulence

noun

  • An emission or expulsion of air from the vagina. 

How often have the words fanny fart and vaginal flatulence occurred in a corpus of books? (source: Google Ngram Viewer )