Sunan Ibn Majah, Book 1, Hadith 517 (In-Book) ⓘ
It was narrated that Busrah bint Safwan said: "The Messenger of Allah said: 'If anyone of you touches his penis, let him perform ablution.'"
حَدَّثَنَا مُحَمَّدُ بْنُ عَبْدِ اللَّهِ بْنِ نُمَيْرٍ، حَدَّثَنَا عَبْدُ اللَّهِ بْنُ إِدْرِيسَ، عَنْ هِشَامِ بْنِ عُرْوَةَ، عَنْ أَبِيهِ، عَنْ مَرْوَانَ بْنِ الْحَكَمِ، عَنْ بُسْرَةَ بِنْتِ صَفْوَانَ، قَالَتْ قَالَ رَسُولُ اللَّهِ ـ صلى الله عليه وسلم ـ " إِذَا مَسَّ أَحَدُكُمْ ذَكَرَهُ فَلْيَتَوَضَّأْ " .
also referenced under: Hadith 479 (Reference) & Volume 1, Book 1, Hadith 479 (DarusSalam)