From Sahih Bukhari (Hadith 269):
Narrated `Ali:I used to get emotional urethral discharge frequently. Being the son-in-law of the Prophet (ﷺ) I requested a man to ask him about it. So the man asked the Prophet (ﷺ) about it. The Prophet (ﷺ) replied, "Perform ablution after washing your organ (penis)
Reference: Bukhari 269