All Praise to Allah Subhan o Taala and blessings on Prophet Muhammad peace be upon him His family and companions
Ali RA narrated: "I asked the Prophet about Al-Madhi. He said: "For
Al-Madhi is Wudu, and for AI-Mani is Ghusl."(Tirmidhi)
I am providing reference according to Hanafi Fiqh
There are three types of fluid 1.Mazi 2.Mani 3.Wadi
Mazi is a thin white fluid which comes due to stimulation and does not need Ghusl but requires wudhu.
Mani is a thick white spurting fluid comes after sexual ejaculation it requires Ghusl if comes due to sexual pleasure or Shahwat.
Wadi is a sticky fluid comes after urination it requires wudhu but does not require Ghusl.
It is mentioned in Al Marja us Sabiq that if mani came and have taken bath before urination and before 40 steps have taken and have performed prayers then the prayer is valid then he sees some fluid it is the remaining mani left at that time and coming out later so he should perform ghusl again.But if person has taken 40 steps or taken a nap and then took bath then it would not be considered as mani and thus does not require Ghusl.
Allah Swt and His Messenger knows best.