What is the ruling on frequent doubt about the emission of madhy (pre-seminal fluid), and how can one ascertain it in public places such as the mosque and school? Does the expansion and rigidity of the penis affect wudu' (ablution) or ritual purity, especially since the questioner sees madhy as transparent and finds it difficult to sprinkle water on his trousers?

Ablution is not nullified merely by doubting the emission of madhy (pre-seminal fluid). Rather, the original state, which is purity, remains until certainty of its emission is attained, based on the hadith: "He should not leave (his prayer) until he hears a sound or finds a smell." If you become certain of the emission of madhy, you must purify the body and clothes affected by it by sprinkling water on them, then perform ablution for prayer. It is not necessary to change clothes. The mere feeling of desire or an erection does not nullify ablution unless one is certain that something has been emitted.