Feeling Drops of Urine After Washing

This may be happening as the
result of waswas (insinuating whispers) and may be something imaginary,
which is from the Shaytan. Or it may really happen to some people. If it is
really happening, he should not rush but wait until the urine has stopped,
then he should wash his private part with water and that is the end of the
matter. If he is worried that something may happen after that, he should
sprinkle the parts of his clothes that are around the private part with
water, then ignore anything that he may imagine after doing wudu, because
this may help him to get rid of this waswas. 

But if it is just his
imagination or waswas, and is not real, then he should not pay any attention
to it. The believer should not pay attention to such things, because this
makes the Shaytan do it more. The Shaytan is keen to spoil the good deeds of
the son of Adam, such as prayer and so on. So, it is essential to be aware
of his tricks and whispers, and to rely on Allah and put one’s trust in Him,
and assume that what doubts he develops are from the Shaytan, so that he
will not take any attention to that with regard to his wudu and then his
prayer. He should not pay attention to any of these imaginary things. Then,
if something really does come out of him, without a doubt, he should clean
himself again and repeat his wudu. 

But as for merely thinking it
happened, he should not pay any attention to it; even if he thinks it is 90%
possible that something has come out of him, he should not pay any attention
to it, because this is something that will make the Shaytan do it to him
again. So as long as he is not certain, he should carry on and pray and do
wudu. Hence when the Prophet (blessings and peace of Allah be upon him) was
asked: O Messenger of Allah, a man thinks that something came out of him
whilst he was praying, he said: “He should not stop [praying] unless he
hears a sound or notices a smell.” So the Prophet (blessings and peace of
Allah be upon him) told them that he should not stop his prayer because of
something he imagines, unless he hears a sound or notices a smell. So
similarly, when a person has finished doing wudu, then he feels something,
he should not go and do wudu again; rather he should continue with his wudu
and prayer and other actions until he is 100% certain that something has
come out. Otherwise, the basic principle is that nothing has come out of him
and that this is waswas and a trick of the Shaytan, with which he tries to
exhaust the believer and distract him by means of these things. We ask Allah
to keep us safe and sound.

End quote. 

Shaykh ‘Abd al-‘Azeez ibn Baz
(may Allah have mercy on him) .