Hormones affects the state of uterine cervix. Cervix is different during menstruation, follicular phase, ovulation, luteal phase, pregnancy. 

I don't want to discuss here the problem of vaginal showers (you can find my topic about it in Period Talk). It is highly controversial. 

However, I will destroy now one myth:

When I'm healthy, pH in my vagina is 3.8..4.5 always, and there is some population of lactobacillus, good bacteria. It is true. But it is not all truth. When woman is in bath tub, she will get some water entrapped into vagina. So, woman has 7.2..7.4...8 pH in her vagina during bathing. After water is gone, the population of lactobacillus will be reduced. It depends on time of immersion, if 20% or 60% of good bacteria population will be saved. If woman is healthy, good bacteria population will restore in 2-3 days, and that return pH to 4 starting from 7 at bath time. 

I have one important rule for vaginal showers: I don't do it in fertile window, but in luteal phase and just after menstruation. 

And I have transferred it to another situation: don't  bath in pool or at plage during fertile window. The cervix is the most opened to outer water, so water can reach even uterus. It is ok if water in vagina, it is normal to it. 

So now I take tickets for vacancy at oceanic plage, and I plan it on my luteal phase, but not on fertile window!

During 10 days that I will enjoy immersion in water I will do vaginal shower with water after plage, and immediately another one vaginal shower for acidification (multi-gyn, Inclear). Each day. 

If you are against vaginal showers, then you should avoid any penetration into your vagina (penis, sex toy), because it could lead to important BV (bacterial vagenosise) or other infection. In the regimen - immersion each day- vagina don't have time to restore good bacteria population. So, even few bad bacteria on penis in condom could trigger BV. If you don't worry about it, and you SO has habit to see his woman in irritated state - you shouldn't pose any limit!