How can i keep from getting bacteria vaginosis?

Good question: Bv may happen without a known reason. However, things you can do--after being treated and clered of bv----be in a monogamous relationship. Next, consider using condoms for a while. If you are experimenting with sexual practices/acts/toys, anal intercourse, etc, perhaps you want to stop for a while and see what happens. Practice good personal hygiene. Consider no underwear or cotton undies.

No reliable way yet: She who discovers how to prevent bacterial vaginosis likely will win a Nobel prize. BV happens to women everywhere. A woman may do better if she uses condoms to keep semen out of her vagina, to avoid more stuff with high pH in there. Current goal is to keep a lower pH to nurture "normal" vaginal living microbes. Good webpage: https://www.uptodate.com/contents/bacterial-vaginosis-beyond-the-basics