Hadith 747
It is narrated from Sayyida Busrah bint Safwan (may Allah be pleased with her), she heard the Messenger of Allah (peace and blessings be upon him) saying: "If a man touches his private part, he should perform ablution." That is, his ablution is broken, and he should renew his ablution for prayer.
Hadith 748
It is narrated from Sayyida Busrah bint Safwan (may Allah be pleased with her) that she heard the Messenger of Allah (peace and blessings be upon him) say: "Whoever touches his private part should perform ablution." Imam Darimi (may Allah have mercy on him) said: This is the most reliable narration regarding the private part.