What should a worshipper do if something comes out of his urethra but does not reach the outside, and this recurs, and the fluid is urine or something else?

What a person feels inside the urethra does not take the ruling of what is external unless it exits beyond the glans and is reached by water. One should disregard what they consider to be excreted while it is still internally, so as not to fall into endless whispers (waswas). Urine that is inside the urethra is not considered impure until it emerges and is reached by water. If one is certain that something has come out externally, then ablution (wudu') is invalidated, and one must repeat istinja' (cleaning oneself) and ablution. If these are doubts or whispers, one should not pay attention to them. Among the things that help in being safe from them is to sprinkle a little water on the penis or on the corresponding part of the garment.