Authentic
No. 445
"If any one of you touches his private part with his hand, let him perform Wudu'."
" إِذَا أَفْضَى أَحَدُكُمْ بِيَدِهِ إِلَى فَرْجِهِ فَلْيَتَوَضَّأْ "
Sunan an-Nasa'iBook 4
The Book of Ghusl and TayammumPage 2
كتاب الغسل والتيمم
53 hadith in this book; 53 translated into English.
Chapter 30Chapter: Wudu' After Touching One's Penis
Authentic
No. 446
"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.'"
" مِنْ مَسِّ الذَّكَرِ "
Authentic
No. 447
"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.
" مَنْ مَسَّ ذَكَرَهُ فَلاَ يُصَلِّي حَتَّى يَتَوَضَّأَ "