What should I do when I doubt whether madhy (prostatic fluid) has exited, and sometimes I find a dry spot or trace, and sometimes I find nothing? And is it permissible for me to use tissues for istijmar (cleaning oneself after urinating or defecating) when water is available?

Doubt regarding the emission of madhy (pre-seminal fluid) is not to be entertained or given attention to, in order to avoid waswasa (whispers of Satan/obsessive thoughts). If its emission is confirmed, one should wash the affected area and perform ablution (wudu') for prayer. If it is found after the prayer and it is probable that it was emitted after the prayer, then it is considered to have occurred subsequent to the prayer, and the prayer does not need to be repeated. However, if it is only probable that it was emitted before the prayer, then the prayer must be repeated.

One should not exaggerate in squeezing the organ when performing istinja' (cleaning oneself after relieving oneself), nor should one delay it. Wiping the urinary opening with a tissue after ensuring the flow has stopped is sufficient. It is best to combine wiping with tissues and using water. If urine spreads beyond the exit point, washing with water becomes obligatory. It is recommended to sprinkle water on the private parts and underwear after istinja' for those who suffer from waswasa concerning the emission of something, in order to alleviate such obsessive thoughts.