It is narrated from Imran bin Muslim (may Allah have mercy on him) that I saw Sayyiduna Anas bin Malik (may Allah be pleased with him) sitting cross-legged in such a way that he had placed one foot over the other.
Hadith Referenceالادب المفرد / كتاب / 1181
Hadith Gradingالألبانی:صحيح
Hadith Takhrij«صحيح : تقدم برقم : 1165م»
Explanation & Benefits
Shaykh Maulana Usman Muneeb
Benefits and Issues: From this, it is understood that sitting cross-legged, placing one foot over the other, is permissible. However, if a person is lying on his back in a single garment, then he should not place one leg over the other so that his awrah (private parts) is not exposed.
Source: Fadlullah al-Ahad: Urdu Commentary on al-Adab al-Mufrad, Page: 1181