مِشْكَاةُ الْمَصَابِيحِ
Mishkat al-Masabih 362
Purification
How to act when relieving oneself - Section 2
وَعَن أُمَيْمَة بنت رقيقَة قَالَتْ: كَانَ لِلنَّبِيِّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ قَدَحٌ مِنْ عَيْدَانٍ تَحْتَ سَرِيرِهِ يَبُولُ فِيهِ بِاللَّيْلِ. رَوَاهُ أَبُو دَاوُد وَالنَّسَائِيّ
Umaima daughter of Ruqaiqa said that the Prophet (ﷺ) had a wooden vessel under his bed in which he passed water at night. Abu Dawud and Nasa’i transmitted it.
Mishkat al-Masabih, 362حسن (الألباني)