What is the ruling on the light white substance that exits without desire, and is it considered a discharge, and does discharge exit from a man?

The jurists (fuqaha') have not discussed any moisture emanating from the male's private parts other than the known secretions. This fluid could be either wady or madhy. Wady is a thick, turbid fluid that exits without pleasure due to an illness or dry nature, and it usually appears after urination. Madhy may exit due to an ailment. Whatever this fluid may be, it is impure (najis), and you must cleanse yourself of it (istibra') and perform ablution (wudu') for prayer. If its discharge is continuous, you must perform ablution for each prayer after its time has begun, and then you may pray the obligatory prayer and whatever supererogatory prayers you wish until that prayer time exits.