The Prophet ﷺ said: “My nation will come forth on the day of judgment like ‘Ghurrah Muhajjaleen’ (horses with white forelocks and white feet)[ Al-Ghurru: is the white patch on the forehead of the horse. Muhajjaleen: are horses with white feet. At-Tahjeel: White patches on their limbs. This refers to the light on the Day of Judgment that will be on the parts of the body that used to be washed during al-wudu’.] as a result of making Al-wudu’. So any of you (who is) capable of lengthening his ghurrah (places of light) should do so.” [ agreed upon.]
1- If a person has a wet dream yet doesn’t ejaculate, he does not have to make ghusl.
2- If he wakes up and doesn’t remember having a wet dream, yet he finds semen on himself, clothes, bed, etc. he must take a ghusl. The Prophet ﷺ said, “Water is only from water.” [ narrated by Muslim.] In other words the emission of semen - willfully or unwillfully - necessitates a ghusl.
3- If he feels semen moving in his penis, yet it does not exit, he does not have to make a ghusl.
4- If it exits due to some sort of sickness and not from sexual stimulation, then he does not have to take a ghusl.
5- If his state necessitated a ghusl, and he took a ghusl, but then semen exited immediately after the ghusl, he is not obliged to take another ghusl. He only has to make wudu’.
6- When a person wakes up from sleep and notices wetness on his clothes whose cause he can’t remember, then the following three conditions are possible:
a) He is sure that the wetness is semen. Then, it is obligatory on him to take a bath, whether he remembers having a wet dream or not.
b) He is sure it is not semen. In this case there is no need to take a bath. The ruling thus will be that of urine (i.e. wudu’).
c) He doubts whether it is semen or not, he must then examine the situation and recall what took place. If it occurs to him that it is semen, then it is semen. However, if it occurs to him that it was something else, then he considers it to be something else. But if nothing occurs to him, then it is compulsory (on him) to take a bath so that he can avoid any error.
7-If he sees semen on himself, but cannot remember when it was produced, it is compulsory to take a bath and repeat the Salah (prayer) from the last time he slept.