Sunan Abi Dawud 8
سنن أبي داود#8HasanNarrated Abu Hurairah:The Apostle of Allaah ( sal Allaahu alayhi wa sallam ) as saying: I am like father to you. When any of you goes to privy, he should not face or turn his back towards the qiblah. He should not cleanse with his right hand. He (the Prophet, sal Allaahu alayhi wa sallam) also commanded the Muslims to use three stones and forbade them to use dung or decayed bone
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Al-AlbaniHasan
Muhammad Muhyi Al-Din Abdul HamidHasan
Zubair Ali ZaiIsnaad Hasan
In-book reference: 1:8