Abdullah ibn AbuBakr reported that he heard Urwah say: I entered upon Marwan ibn al-Hakam. We mentioned things that render the ablution void. Marwan said: Does it become void by touching the penis? Urwah replied: This I do not know. Marwan said: Busrah daughter of Safwan reported to me that she heard the Messenger of Allah ﷺ say: He who touches his penis should perform ablution. (Using translation from Abū Dāʾūd 181)
أَنَّهَا سَمِعَتْ رَسُولَ اللهِ ﷺ يَقُولُ «مَنْ مَسَّ ذَكَرَهُ فَلْيَتَوَضَّأْ»