Abdullah bin Abbas reported,

Ali, Miqdad, and Ammar were discussing a matter together. Ali said, "I am a man who experiences frequent prostatic discharge, but I feel too shy to ask the Messenger of Allah ﷺ about it because of my marriage to his daughter. So one of you, please ask him."He mentioned to me that one of them, though I have forgotten which, asked him. The Prophet ﷺ said, "That is prostatic fluid. When any of you finds it, let him wash that part of his body and perform ablution as he does for prayer," or he said, "like the ablution for prayer."

Nasai 436

Sahih

أخبرنا علي بن ميمون قال حدثنا مخلد بن يزيد عن ابن جريج عن عطاء

عن ابن عباس قال

تذاكر علي والمقداد وعمار فقال علي إني امرؤ مذاء وإني أستحي أن أسأل رسول الله ﷺ لمكان ابنته مني فيسأله أحدكما فذكر لي أن أحدهما ونسيته سأله فقال النبي ﷺ ذاك المذي إذا وجده أحدكم فليغسل ذلك منه وليتوضأ وضوءه للصلاة أو كوضوء الصلاة.

النسائي 436صحيح
Contents
Reference
Commentary
Ayat
Collection
Sunan Nasai Sughra
Book
Ghusl and tayammum
Chapter
Wudu due to madhi
Numbering
Darussalam 436
Nasai 436