Ma'qil bin Yasar (may Allah be pleased with him) narrates that when the Messenger of Allah (peace and blessings be upon him) placed Nu'aym bin Mas'ud in the grave, he pulled out the pins fastening the shroud with his mouth.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الجنائز / 6714
Uthman, the nephew of Sayyiduna Samurah (may Allah be pleased with him), narrates that a son of Sayyiduna Samurah (may Allah be pleased with him) died, and he said to me: Go with him to his grave, and when you place him in his niche (lahd), say: 'Bismillah wa 'ala sunnati Rasulillah' (In the name of Allah and upon the Sunnah of the Messenger of Allah (peace and blessings be upon him)). Then untie the knot at his head and the knot at his feet.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الجنائز / 6715