Narrated Mughira bin Shu'ba:

Once I was traveling with the Prophet and he said, "O Mughira! take this container of water." I took it and Allah's Apostle went far away till he disappeared. He answered the call of nature and was wearing a Syrian cloak. He tried to take out his hands from its sleeve but it was very tight so he took out his hands from under it. I poured water and he performed ablution like that for prayers and passed his wet hands over his Khuff (leather socks) and then prayed .

حَدَّثَنَا يَحْيَى، قَالَ حَدَّثَنَا أَبُو مُعَاوِيَةَ، عَنِ الأَعْمَشِ، عَنْ مُسْلِمٍ، عَنْ مَسْرُوقٍ، عَنْ مُغِيرَةَ بْنِ شُعْبَةَ، قَالَ كُنْتُ مَعَ النَّبِيِّ ﷺ فِي سَفَرٍ فَقَالَ " يَا مُغِيرَةُ، خُذِ الإِدَاوَةَ ". فَأَخَذْتُهَا فَانْطَلَقَ رَسُولُ اللَّهِ ﷺ حَتَّى تَوَارَى عَنِّي فَقَضَى حَاجَتَهُ، وَعَلَيْهِ جُبَّةٌ شَأْمِيَّةٌ، فَذَهَبَ لِيُخْرِجَ يَدَهُ مِنْ كُمِّهَا فَضَاقَتْ، فَأَخْرَجَ يَدَهُ مِنْ أَسْفَلِهَا، فَصَبَبْتُ عَلَيْهِ فَتَوَضَّأَ وُضُوءَهُ لِلصَّلاَةِ، وَمَسَحَ عَلَى خُفَّيْهِ، ثُمَّ صَلَّى.