

When fertile, women have significantly increased mucus volume in their vaginas.
https://en.wikipedia.org/wiki/Cervix
Several hundred glands in the endocervix produce 20–60 mg of cervical mucus a day, increasing to 600 mg around the time of ovulation.

I, a vagina-haver, had no idea until a Catholic friend in college mentioned NFP. The secular Fertility Awareness resources I ended up finding all supported my impression this isn’t widely known. That was twenty years ago, though, maybe young people these days are more body-aware?
Agree it isn’t really gross, I think it’s cool, but it seemed gross-adjacent enough I could get away with sharing in this thread.