ENOfficial
Busra daughter of Safwan b. Naufal reported God’s messenger as saying, “If any of you touches his penis he must perform ablution.” Malik, Ahmad, Abu Dawud, Tirmidhi, Nasa’i, Ibn Majah and Darimi transmitted it.
Source: sunnah.com
Other translations
Arabic
وَعَن بسرة قَالَتْ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: «إِذَا مَسَّ أَحَدُكُمْ ذَكَرَهُ فَلْيَتَوَضَّأْ» . رَوَاهُ مَالِكٌ وَأَحْمَدُ وَأَبُو دَاوُدَ وَالتِّرْمِذِيُّ وَالنَّسَائِيُّ وَابْنُ مَاجَه والدارمي
sunnah.com