How can a person afflicted with OCD be sure of the emission of pre-seminal fluid (madhy), and does it leave a trace?

You must ignore the whispers concerning the emission of pre-seminal fluid (madhy), and do not judge it to have exited unless you achieve absolute certainty of it. If you become certain of its emission and find its characteristic trace on your ذكر (male organ) or clothes, then you are obliged to purify yourself from it. But without this certainty, the original state is purity.