Sunan an-Nasa'i 193
سنن النسائي#193SahihIt was narrated that 'Ali said:"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
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Abu GhuddahSahih
Al-AlbaniSahih
Zubair Ali ZaiIsnaad Sahih
In-book reference: 1:194