Abdullah bin Abi Qatadah reports from his father, Sayyiduna Abu Qatadah (may Allah be pleased with him), that the Prophet (peace and blessings be upon him) said: "When one of you goes to the toilet, he must not clean himself with his right hand, nor touch his private part with his right hand."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 544
It is narrated from Sayyiduna Salman (may Allah be pleased with him) that the polytheists said to him: "We see that your companion (the Prophet, peace and blessings be upon him) teaches you even the manner of sitting to relieve yourselves!" He said: Yes. Indeed he forbade us that any of us should clean himself with his right hand or face the qiblah, and he forbade us dung and bones, and he (peace and blessings be upon him) said: "None of you should clean himself with fewer than three stones."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 545
It is narrated from Sayyiduna Abu Hurayrah (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) said: "I am to you like a father; I teach you. When one of you goes to the toilet, he should neither face the qiblah nor turn his back to it, nor clean himself with his right hand." He (peace and blessings be upon him) used to order us to use three stones and forbade dung and decayed bone.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 546
Sayyidah Hafsah (may Allah be pleased with her) relates that the Prophet (peace and blessings be upon him) used to keep his right hand for eating, drinking and his clothing, and his left hand for other matters.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 547
Sayyidah Aishah (may Allah be pleased with her) said: The right hand of the Messenger of Allah (peace and blessings be upon him) was for his purification, eating and drinking, and his left hand was for the toilet and other filth.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 548