Tightness Of Clothes And Wudhu
The moisture contain some urine. Is it really negligible? Because about this place, scholar Ibn Qudamah (may Allah have mercy on him) said: “If one drops oil into his urethra, then it comes out again, it invalidates Wudu, because it came out of the passage, which cannot be free of some impure wetness that accompanies it. Therefore Wudu is invalidated thereby, just as when only impurity comes out.” (Al-Mughni 1/125)
Also please see this.
Ablution should not be made right after urination. Let it be dried and then make ablution. There comes no moisture out. What comes out is either semen or urine drops that invalidate Wudu. if the garment touches the moisture inside urethral (which is usually not possible, but for the sake of argument) then it does not invalidate Wudu.