One who suffers from Continuing Urine
Question :
If someone suffers from continuing urine, is it permissible to delay his urination until after the prayer is over?
Answer:
Whoever suffers from continuing urine, he must seek a cure for it, to the best of his ability. But if it is due to delusions and the whisperings of Satan, he should pay no attention to it, for it is considered to be in its original state, which is one of purity, unless it is definitely proven that something has been emitted which invalidates the ablution. If the emission of urine is continuous and unceasing, he may pray in that state, but if he is able to reduce it, he must do so, even if it be by placing a scrap of material or some such thing over the head of the penis, or wrapping it in a covering, so that the urine does not soil his clothing. If it does not come out except after passing urine, he must urinate some while before prayer to give sufficient time for the dribbling to stop and he should wash his groin with water, because washing it with cold water prevents its emission. But he should be careful that the time spent in urination is not too long, and if he fears that it will go on for a long time, and he will miss the prayer, he may delay it until after the prayer, if this does not cause burning or severe retention, which will distract him from his prayers. And Allah knows best.
Source:
Ibn Jibreen
Fatawa Islamiyah, Vol. 2 Page 24