The Emission of Semen during Sleep
Question :
Does the emission of semen during sleep require Ghusl? And what are the things which necessitate Ghusl?
Answer:
Yes, whoever has a nocturnal emission of sperm is obliged to make Ghusl, even if he does not remember having any sexual dreams, but Ghusl is not required for one who dreams without ejaculation.
Ghusl is required for the nocturnal emission of semen, and it is not required for its emission when awake, when it flows like urine and there is no sexual arousal involved, but if it spurts out due to sexual arousal, then Ghusl is necessary, and Ghusl is required after sexual intercourse, even if ejaculation does not take place, so long as the (male and female) sexual organs have been in contact.
Source:
Ibn Jibreen
Fatawa Islamiyah, Vol. 2 Page 95