When is Ghusl required?
It seems that this wetness that you feel is Madhiy and not maniy , the emission of which (i.e., if it was maniy ) means that you must do Ghusl.
Based on this, you do not have to do Ghusl when it is emitted, you only have to do Wudu, because the emission of Madhiy invalidates Wudu, as the Prophet (peace and blessings of Allah be upon him) said concerning Madhiy: “Wudu is required for it.” (Narrated by Al-Bukhari and Muslim)
Ibn Qudamah (may Allah have mercy on him) said in Al-Mughni (1/168): “The scholars unanimously agreed that the emission of Madhiy invalidates Wudu .”
Is Madhiy impure?
It must be noted that Madhiy is impure, and any part of the body that it touches must be washed. As for clothing , Islam is lenient about purifying it so as to ward off hardship. It is sufficient for you to take a handful of water and sprinkle it on the place that has been touched by Madhiy. When the Messenger (peace and blessings of Allah be upon him) was asked about how to cleanse a garment of Madhiy , he said: “It is sufficient for you to take a handful of water and sprinkle your garment where you think the Madhiy touched it .” (Narrated by At-Tirmidhi (115); classed as sound by Al-Albani in Sahih At-Tirmidhi)
And Allah knows best.