It is narrated from Sayyidah Aisha (may Allah be pleased with her), she says: Indeed, the Messenger of Allah (peace and blessings be upon him) would be performing prayer and I would be lying down sometimes on his right side and sometimes on his left side.
Hadith Referenceالفتح الربانی / أبواب الأذ كار الواردة عقب الصلاة / 1968