Peace be upon you. According to Grand Ayatollah Sayyid Sistani (may Allah preserve him), if a woman experiences fluid release due to arousal and it is enough to stain her underwear, it is considered an emission (ejaculation) if it occurs with strong sexual excitement and reaching the peak, which is referred to as sexual climax. This is also applicable even if she does not reach the peak, as a precaution. However, if the fluid is released without arousal or is just a slight moisture that does not exceed the vaginal area due to light sexual stimulation, it does not cause ritual impurity and is considered pure. If there is doubt about the fluid's release or its extent, there is no need for purification, and it does not invalidate ablution or ritual washing. There is no need to investigate doubts, and light moisture on clothing does not count as an emission. This ruling applies equally whether one is awake or asleep. Furthermore, all scholars clearly state that a person who is scrupulous (waswasa) should disregard their doubts and assume purity regarding anything they are uncertain about. Even if they are certain of something being impure, they should not rely on that certainty and must assume it is pure. If a scrupulous person follows this religious ruling and assumes purity for everything they doubt, even if they are certain of impurity, they are excused before Allah, even if their actions contradict reality, such as praying in a state of impurity or consuming impure food. Source: Official website links provided for further reading.