Sayyiduna Abdullah bin Zayd bin Asim Mazani (may Allah be pleased with him) says that I saw the Prophet (peace and blessings of Allah be upon him) lying on his back, with one foot placed over the other.
Hadith Referenceالادب المفرد / كتاب / 1185
Hadith Gradingالألبانی:صحيح
Hadith Takhrij«صحيح : أخرجه البخاري ، كتاب الاستئذان : 6287 و مسلم : 2100 و أبوداؤد : 4866 و الترمذي : 2765 و النسائي : 721»
Explanation & Benefits
Shaykh Maulana Usman Muneeb
Benefits and Issues: In some narrations, it is mentioned that the Prophet sallallahu alayhi wa sallam forbade lying down in this manner. Imam Nawawi rahimahullah reconciled between these narrations by stating that the prohibition applies in the case where there is a risk of the awrah (private parts) being exposed, and if a person is cautious and there is no fear of any kind of exposure, then lying down in this way is permissible. Some scholars have said that the prohibition is for the sake of dislike (karahah), and the action of the Prophet sallallahu alayhi wa sallam is to indicate permissibility—that in a situation of need, when there is no fear of the awrah being exposed, it is permissible to lie on one’s back and place one leg over the other in this manner. However, it is better and more virtuous not to adopt this posture. (Sharh Sahih al-Adab al-Mufrad)
Source: Fadlullah al-Ahad: Urdu Commentary on al-Adab al-Mufrad, Page: 1185