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 min sharri mani (O Allah, protect me from the evil of my hearing, my seeing, my tongue and my heart, and from the evil of my sperm.)'" - Meaning sexual organ.
أَخْبَرَنَا عُبَيْدُ بْنُ وَكِيعِ بْنِ الْجَرَّاحِ، 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 وَمِنْ شَرِّ مَنِيِّي " . يَعْنِي ذَكَرَهُ .
Nesai
The Book of Seeking Refuge with Allah • Hadith 5456