What should one do if they doubt the emission of pre-seminal fluid (madhy), then become predominantly certain of its emission, then the matter becomes equal for them, then they become predominantly certain of its emission again?

Whoever doubts the emission of madhy (pre-seminal fluid) should not pay attention to the doubt nor inspect himself, for the default state is purity, and one does not deviate from this default except with certainty. If its emission is highly probable, one should act upon certainty. Sheikh Ibn Baz advised the questioner, who felt madhy exiting when leaving home or after the mosque, that if the emission of madhy was incidental, he should treat it by performing istinja' (washing the private parts) and sprinkling water around the private parts during wudu' (ablution), and if he had the slightest doubt, he should disregard it. However, if it is constant and continuous, it is similar to sals (incontinence), and in such a case, he should perform wudu' when the prayer time enters and then pray. He also advised the questioner not to indulge in excessive assumptions and scrutiny, and to turn away from waswas (whispers of Satan). If it causes him suffering, he should consult a specialized doctor.