Uthman ibn 'Affaan · The Book of Purification and its Sunnah

"I heard the Messenger of Allah say: 'Whoever touches his sexual organ, let him perform ablution.'"

"I heard the Messenger of Allah being asked about touching the penis. He said: 'That does not require ablution, because it is a part of you (your body).'"

"We did dry ablution with the Messenger of Allah, (wiping our arms) up to our shoulders."

The Prophet said: "The five daily prayers, from one Friday to the next, and fulfilling the trust are all expiation for whatever (sins) come between them." I said: "What is fulfilling the trust?" He said: Having a bath to cleanse oneself from sexual impurity, for under every hair there is the state of sexual impurity."