What should you do if dryness occurs during menstruation or yellowish discharge, but you do not perform ghusl for fear of yellowish discharge or drops of blood coming out during ghusl? And do cooking oil and food fats around the mouth after eating prevent water from reaching during wudu? And is it possible for semen to separate and fall during urination upon waking up from sleep?

If dryness occurs during menstruation and you know that the blood will return before the prayer time expires, then ghusl (definition) (ritual bath) is not obligatory. However, if you know it will return after the prayer time has elapsed, or if you are in doubt, then ghusl and performing the prayer become obligatory. Residual oils around the mouth do not affect the validity of wudu (ablution) or ritual purity, unless they are solidified and have a palpable mass. It is not necessary to check the private parts upon waking up for fear of semen, as the certainty of its non-emission is the original state.