Ibn 'Umar (RAA) narrated that the Messenger of Allah (ﷺ) said:
"Avoid these filthy practices which Allah, the Almighty has prohibited. He who commits any of these, should conceal with Allah's Most High Veil (i.e. should not speak about it), and should turn to Allah, the Most High in repentance, for if anyone uncovers his hidden sins (to us), we shall inflict on him the punishment prescribed by Allah, the Al-Mighty." Related by Al-Hakim and in Al-Muwatta' but traced to its narrator Zaid bin Aslam as hadith Mursal.
English reference: Book 10, Hadith 1261
Arabic reference: Book 10, Hadith 1222