Vaginal flatulence normal?

Hi! Over the past year I''ve experienced (rarely) what I can only describe as vaginal flatulence. It''s odorless and I don''t have any pain or other major symptoms, which is why I haven''t asked my doctor. But now, reading that it''s not normal, I''m starting to wonder what to think. It''s not related to sex. When it happens, I stand up and there is a fast rush of air through my vagina and noise like flatulence. It happens so fast I don''t know what hit me. Otherwise, sometimes I''ll feel air bubbles through my vagina, too. Again, this isn''t all the time. But when should I be worried? Thanks!