Must one urinate a large amount after intercourse or a wet dream, and must one repeat the prayer if a clear white fluid is found to have exited after its performance, and is it permissible to interrupt the prayer to verify the exit of this fluid, and what is the ruling on purifying clothes from it?

There is no obligation for a person in a state of janabah (major ritual impurity due to sexual intercourse or a wet dream) to urinate after intercourse or a wet dream; it is sufficient for him to wash the area of impurity. As for the white fluid that sometimes exits after arousal, it is madhi (pre-seminal fluid), and one must wash whatever it touches, wash the penis, and perform ablution (wudu') for prayer. If it exits during prayer, the prayer becomes invalid and must be repeated. If it is found after prayer, the prayer remains valid if its exit could have occurred after the prayer; otherwise, it becomes invalid and must be repeated. It is not permissible to interrupt the prayer to verify the exit of the fluid if there is doubt about it. If the exit of this fluid is continuous, it is considered سلس (urinary incontinence or constant discharge) and has its own specific rulings. It is obligatory to wash whatever clothes are soiled by this fluid or any other impurities. Washing the affected area is sufficient, or the entire garment if the soiled spot is indistinguishable.