(34) CHAPTER. Whosoever considers not to repeat ablution except if something is discharged or passed from either exit (front or back private parts).
Narrated `Ali: I used to get emotional urethral discharges frequently and felt shy to ask Allah's Apostle about it. So I requested Al-Miqdad bin Al-Aswad to ask (the Prophet ) about it. Al-Miqdad asked him and he replied, On has to perform ablution (after it).
Authentic