وَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ إِسْمَاعِيلَ بْنِ مُحَمَّدِ بْنِ سَعْدِ بْنِ أَبِي وَقَّاصٍ، عَنْ مُصْعَبِ بْنِ سَعْدِ بْنِ أَبِي وَقَّاصٍ، أَنَّهُ قَالَ كُنْتُ أُمْسِكُ الْمُصْحَفَ عَلَى سَعْدِ بْنِ أَبِي وَقَّاصٍ فَاحْتَكَكْتُ فَقَالَ سَعْدٌ لَعَلَّكَ مَسِسْتَ ذَكَرَكَ قَالَ فَقُلْتُ نَعَمْ ‏.‏ فَقَالَ قُمْ فَتَوَضَّأْ فَقُمْتُ فَتَوَضَّأْتُ ثُمَّ رَجَعْتُ ‏.‏

Yahya related to me from Malik from Ismail ibn Muhammad ibn Sadibn Abi Waqqas that Musab ibn Sad ibn Abi Waqqas said, "I was holdingthe Book for Sad ibn Abi Waqqas and I rubbed myself. Sad said, 'Didyou touch your penis?' I replied, 'Yes,' and he said, 'Get up and dowudu.' So I got up and did wudu and then returned." Translation Not Available

Book Ref: Muwatta Imam Malik Book 2 Hadith 91
Web Ref:  Muwatta Imam Malik Book 2 Hadith 61