Marwan brought up the matter of touching the male organ with me, and I said that it does not require ablution.He replied, "Busra bint Safwan narrates that it does."So he sent a messenger to her, and the messenger reported that she narrated that the Messenger of Allah ﷺ said, "Whoever touches his male organ must perform ablution."
حدثنا إسماعيل ابن علية قال حدثنا عبد الله بن أبي بكر بن حزم قال سمعت
ذاكرني مروان مس الذكر فقلت ليس فيه وضوء فقال إن بسرة بنت صفوان تحدث فيه فأرسل إليها رسولا فذكر الرسول أنها تحدث أن رسول الله ﷺ قال من مس ذكره فليتوضأ
Its isnad is sahih, and it has already appeared at 2185, along with mention of the disagreement about it.