What comes out following urination is usually wadiy, which is a thick, white liquid that comes out in the form of drops. As for madhiy (prostatic fluid), it is what comes out following provocation of desire.
Both of them invalidate wudoo', but they do not necessitate ghusl. When you say, When it comes out I do ghusl, perhaps you mean that you wash it. As for ghusl (full ablution), you do not have to do it; rather you have to do wudoo'.
An-Nawawi (may Allah have mercy on him) said, explaining the difference between madhiy and wadiy: As for madhiy, it is a sticky, thin, clear fluid that is emitted with or without desire; it does not gush out in spurts, and it is not followed by exhaustion; and one may not feel it coming out. It happens to both men and women.
As for wadiy, it is a thick, darkish fluid that resembles maniy (semen) in its thickness, but differs from it in colour, and it has no smell. It comes out following urination, when one is constipated, or when carrying something heavy, and it comes out in the form of one or two drops and the like. The scholars are unanimously agreed that it is not required to do ghusl when madhiy and wadiy are emitted.
End quote from al-Majmoo, 2/160
Shaykh Ibn Jibreen (may Allah preserve him) was asked: At the end of urination, I notice some seminal fluid (maniy) coming out, and I do not know whether I have to do ghusl every time I urinate, or what should I do? Because I am not sure whether it has the same effect as intercourse?
He replied: This maniy that comes out after urination is wadiy, which is well known (and is not actually maniy). As it comes out after urination and comes out in a stream (as opposed to gushing out), it does not necessitate ghusl. However it does invalidate wudoo', so the penis should be washed after that, then one should do wudoo', but it is not necessary to do ghusl. Ghusl is only required when maniy gushes out in spurts accompanied by feelings of pleasure, and is not required otherwise. As gushing out in spurts forcefully is not like the emission of urine, which comes out in a stream or in drops, it does not matter if it comes out like that.
End quote from Fataawa Islamiyyah, 1/226
When you have relieved yourself, you have to wait until you are certain that the flow has stopped, then clean yourself and do wudoo'. If that leads to you missing the prayer in congregation, there is no blame on you. But you should get ready for the prayer before the time comes, so long as you know that you need a long time to relieve yourself.
The Standing Committee for Issuing Fatwas were asked: There is a man who suffers from urinary incontinence. He purifies himself some time after urinating, but if he were to wait until the incontinence ends, the time for the prayer in congregation would be over. What is the ruling?
They replied: If he knows that the incontinence will end, it is not permissible for him to pray when it is still affecting him, seeking the virtue of praying in congregation. Rather he has to wait until it ends, then he should clean himself after that, then do wudoo' and offer his prayer, even if he misses the prayer in congregation. However he should hasten to clean himself and do wudoo' once the time for the prayer has begun, in the hope that he will be able to pray in congregation. End quote.
Fataawa al-Lajnah ad-Daa'imah, 5/408
Shaykh Ibn Jibreen (may Allah preserve him) said concerning the one who is faced with that problem:
First of all you have to take precautions with regard to purification. So do wudoo' half an hour or so before the time for prayer begins, after you have urinated and the effects of urination have ceased, in the hope that it will stop before the time for prayer comes.
Secondly, after urinating you have to wash your private part with cold water that will stop urination and prevent drops coming out.
If these drops are the result of waswaas (whispers from the Shaytaan) or something imaginary, then after cleaning yourself you should sprinkle water on your pants or thobe, so that the Shaytaan cannot make you imagine, if you see dampness, that it is urine, because you will know that it is water that you put on your garment.
End quote from Fataawa Islamiyyah, 1/196
You should beware of waswasah (whispers from the Shaytaan), for it is a disease and an evil that can cause a person to worry and generate doubt in his mind, making worship burdensome for him. So beware of that. When you have relieved yourself, done wudoo' and prayed, do not pay any attention to doubts, because the basic principle is that one is pure and that prayers are valid.
Shaykh Ibn Uthaymeen (may Allah have mercy on him) was asked: When I have finished wudoo' and am going to pray, I feel a drop of urine coming out of the penis; what should I do?
The one who is affected with that should ignore it, as enjoined by the leading scholars of the Muslims. He should not pay any attention to it or go and check whether anything came out or not. By Allah's leave, if he seeks refuge with Allah from the accursed Shaytaan and ignores it, it will go away. But if he is utterly certain about it, then it is essential to wash whatever the urine has gotten onto, then repeat his wudoo' because some people, if they feel coldness at the tip of the penis, think that something has come out. But if you are certain, you should do what I told you. What you have mentioned is not incontinence, because it stops, whereas incontinence is ongoing. As for this, it is one or two drops that come out after moving; this is not incontinence because two drops come out then it stops. In this case you should wash yourself and do wudoo' again. You should always do this, and be patient and seek reward with Allah.
End quote from Liqa' al-Baab al-Maftooh, 184/15
And Allah knows best.
Reproduced from Islam QA