If due to sexual thoughts, a vaginal discharge flows and it’s not seminal discharge, then it’s a madhi. According to Sheikh Sayyed Sabiq in his well-known book, Fiqh As-Sunnah, “madhi is a white sticky fluid that flows from the sexual organs because of thinking about sexual intercourse or foreplay, and so on. The person is usually not aware of when exactly it is secreted. It comes from both the male and the female sexual organs, although the amount from the latter is usually more than the former. Scholars agree that it is impure. If it gets on the body, it is obligatory to wash it off. If it gets on the clothes, it suffices to sprinkle the area with water, as
It is very hard to be completely protected from this impurity, especially for the young, single person.”
Moreover, if vaginal discharge (seminal discharge) flows after a lady perform ghusl to purify herself after intercourse, then she is not required to re-make ghusl as long as that vaginal discharge that flows after ghusl is not caused by sexual thought, desire, or practice.