Rubayh bin Abd al-Rahman narrates from his father, from his grandfather Sayyiduna Abu Sa'id al-Khudri (may Allah be pleased with him), that when the Messenger of Allah (peace and blessings be upon him) sat in a gathering, he would sit with his knees drawn up, holding them with his hands.
Abdullah bin Ibrahim al-Ghifari is alone in narrating it, and he is a shaykh who is munkar al-hadith (his narrations are rejected); Abu Dawud al-Sijistani and others said so.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الجمعة / 5916