It is narrated from Sayyiduna Abu Umamah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "When one of you goes to his wife, let him put a covering (cloth) over himself and his wife." He said: "And let the two of them not be naked like donkeys."
Hadith Referenceالمعجم الكبير للطبراني / باب الصاد / 7652