Abdullah bin Wahb عبد الله بن وهب بن مسلم القرشي · The Book of Ghusl and Tayammum

"I was a man who emotted a great deal of Madhi. I told a man to ask the Prophet (ﷺ) (about that) and he said: 'Wudu' (is required) for that."

"Whoever touches his penis, he should not perform Salah until he performs Wudu'." Abu 'Abdur-Rahman (An-Nasa'i) said: Hisham bin 'Urwah did not hear this Hadith from his father.