Well, if she did have a yeast infection, someone eating her out (most likely with sugar, or something foreign in their mouth) would exacerbate it. Maybe recovering from one, or it could've been her Herpes medicine.

I've been eating the cleanest pussy for five years, and the only time there's been white discharge (that I knew of) was when she'd apply the medicine, whether she had it or not (Yeast I., not herpes). If it is a yeast infection, the mucus won't be clear white. Did you ever think of baby powder? j/k