Umar b. al-Khattab said to the Messenger of Allah (ﷺ), that he became Junbi during the night. The Messenger of Allah (ﷺ) said to him: Perform ablution, wash your sexual organ and then go to sleep.
Sahih Muslim Book 3, Hadith 26
← Previous Hadith 'Umar asked the verdict of the Shari'ah from the Apostle (ﷺ) thus: Is it permissible for any one of us to sleep in a state of impurity? He (the Prophet said: Yes, he must perform ablution and then sleep and take a bath when he desires.

Sahih Muslim Book 3, Hadith 25 Next Hadith → I asked 'A'isha about the Witr (prayer) of the Messenger of Allah (ﷺ) and made mention of a hadith, then I said: What did he do after having sexual intercourse? Did he take a bath before going to sleep or did he sleep before taking a bath? She said: He did all these. Some- times he took a bath and then slept, and sometimes he performed ablution only and went to sleep. I (the narrator) said: Praise be to Allah Who has made things easy (for human beings).

Sahih Muslim Book 3, Hadith 27