"I was one who had a lot of prostatic discharge, and the Messenger of Allah ﷺ said to me: 'If you see Madhi (prostatic fluid) then wash your penis and perform Wudu' like that for Salah, but if you ejaculate semen, then perform Ghusl.'" (Using translation from Nasāʾī 193)  

رَسُولُ اللهِ ﷺ «إِذَا رَأَيْتَ الْمَذْيَ فَاغْسِلْ ذَكَرَكَ وَتَوَضَّأَ وُضُوءَكَ لِلصَّلَاةِ وَإِذَا فَضَخْتَ الْمَاءَ فَاغْتَسِلْ»  

I was a man who emitted a great deal of madhi, so I asked the Prophet ﷺ and he said: “If you see madhi then do wudoo’ and wash your private part, and if you see water gushing then do ghusl.ʿ I [the narrator] mentioned that to Sufyan and he said: I heard that from Rukain. Muʿawiyah and ibn Abi Bukair told us: Zaʿidah told us: ar-Rukain bin ar-Rabee bin ‘Ameelah al-Fazari told us... And he mentioned a similar report, and they said: water gushing. And Ibn Abu Bukair told us: Zaʿidah told us, and he also said, gushing. (Using translation from Aḥmad 1028)  

كُنْتُ رَجُلًا مَذَّاءً فَسَأَلْتُ النَّبِيَّ ﷺ فَقَالَ «إِذَا رَأَيْتَ الْمَذْيَ فَتَوَضَّأْ وَاغْسِلْ ذَكَرَكَ وَإِذَا رَأَيْتَ فَضْخَ الْمَاءِ فَاغْتَسِلْ»