I want to be Freeuse for my gf but I need hygiene advice

I want to open up the option to my gf to always be available for her whenever she wants. (Mainly oral) My only concern is that I know a lot of things can throw off a woman’s PH and I just need a little advice/ tips for what I can do throughout the day orally to make sure I’m not throwing of my girlfriends PH. I’m assuming brushing my teeth throughout the day is smart but I don’t know if toothpaste could be bad I just need help 😅