Praise be to Allah.
Shaykh Ibn ‘Uthaymeen was asked about this fluid that comes out after doing ghusl from janaabah (impurity following sexual activity), and he replied:
This fluid which comes out after doing ghusl from janaabah, if there is no new arousal which led to its emission, then it is a leftover from what was there from the first instance of janaabah, so it is not necessary to do ghusl from it. Rather the person should wash it away and wash whatever it touches, and repeat wudoo’ only.
Fataawa Ibn ‘Uthaymeen, 11/222
In Zaad al-Mustaqni’ it says: “If it comes out afterwards, do not repeat (ghusl).”
Shaykh Ibn ‘Uthaymeen (may Allaah have mercy on him) said: i.e., if he does ghusl for this that has come out (i.e., maniy or semen), then it comes out when he moves, then he does not have to do ghusl (again). The evidence for this is:
That the cause is the same, so there is no need to do two ghusls.
Because it comes out after that without feelings of pleasure, and ghusl is not obligatory except when it comes out accompanied by feelings of pleasure.
See al-Sharh al-Mumti’ by Ibn ‘Uthaymeen, 1/281, and Allaah knows best.