The Prophet ﷺ forbade wrapping oneself in the Samma manner, and forbade a man from sitting with his knees drawn up in a single garment with nothing covering his private parts.
حدثنا روح حدثنا ابن جريج أخبرني ابن شهاب عن عبيد الله بن عبد الله
أن النبي ﷺ نهى عن اشتمال الصماء وأن يحتبي الرجل في ثوب واحد ليس على فرجه منه شيء
Its isnad is sahih. Ubaydullah bin Abdullah bin Umar is the full brother of Salim bin Abdullah the jurist, and Ibn Jurayj is Abdul-Malik bin Abdul-Aziz bin Jurayj, a well-known imam. The hadith has already appeared at 9389.