"Busrah bint Safwan told me that." 'Urwah sent someone to check that, and she said: "The Messenger of Allah ﷺ mentioned what Wudu' is done for, and said: 'Touching the penis.'"
مَرْوَانُ أَخْبَرَتْنِيهِ بُسْرَةُ بِنْتُ صَفْوَانَ فَأَرْسَلَ عُرْوَةُ قَالَتْ ذَكَرَ رَسُولُ اللَّهِ ﷺ مَا يُتَوَضَّأُ مِنْهُ فَقَالَ مِنْ مَسِّ الذَّكَرِ