What should I do if I feel something exiting the male organ during prayer?

The most accurate view is that anything that exits from the two private parts (front and back) invalidates ablution, whether little or much, such as feces, urine, gas, blood, and so on. Scholars have used the hadith: "No, unless he hears a sound or perceives a smell" as evidence that purity is not invalidated by doubt, but rather by certainty. Therefore, if you are certain that something has exited during prayer, your ablution has been invalidated, and you must exit the prayer, perform ablution, and then resume the prayer.