It was narrated from Shutair bin Shakal bin Humaid, that his father said:"I said: 'O Messenger of Allah, teach me a supplication from which I may benefit.' He said: 'Say: Allahumma 'afini min sharri sam'i, wa basari, wa lisani, wa qalbi, wa sharri mani (O Allah, protect me from the evil of my hearing, my seeing, my tongue and my heart, and the evil of my sperm.)" - Meaning his sexual organ.
أَخْبَرَنِي عُبَيْدُ بْنُ وَكِيعٍ، قَالَ حَدَّثَنَا أَبِي، عَنْ سَعْدِ بْنِ أَوْسٍ، عَنْ بِلاَلِ بْنِ يَحْيَى، عَنْ شُتَيْرِ بْنِ شَكَلِ بْنِ حُمَيْدٍ، عَنْ أَبِيهِ، قَالَ قُلْتُ يَا رَسُولَ اللَّهِ عَلِّمْنِي دُعَاءً أَنْتَفِعُ بِهِ . قَالَ " قُلِ اللَّهُمَّ عَافِنِي مِنْ شَرِّ سَمْعِي وَبَصَرِي وَلِسَانِي وَقَلْبِي وَشَرِّ مَنِيِّي " . يَعْنِي ذَكَرَهُ .
Nesai
The Book of Seeking Refuge with Allah • Hadith 5484