Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) said that Sayyiduna Umar (may Allah be pleased with him) said: O Messenger of Allah (peace and blessings be upon him)! If I become junub, what should I do? He (peace and blessings be upon him) said: "Wash your private part, perform ablution, then sleep."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب النكاح / 14093