Sahih al-Bukhari 367
Narrated Abu Sa`id Al-Khudri:
Allah's Messenger (ﷺ) forbade Ishtimal-As-Samma' (wrapping one's body with a garment so that one cannot 
raise its end or take one's hand out of it). He also forbade Al-Ihtiba' (sitting on buttocks with knees 
close to `Abdomen and feet apart with the hands circling the knees) while wrapping oneself with a 
single garment, without having a part of it over the private parts.
حَدَّثَنَا قُتَيْبَةُ بْنُ سَعِيدٍ، قَالَ حَدَّثَنَا لَيْثٌ، عَنِ ابْنِ شِهَابٍ، عَنْ عُبَيْدِ اللَّهِ بْنِ عَبْدِ اللَّهِ بْنِ عُتْبَةَ، عَنْ أَبِي سَعِيدٍ الْخُدْرِيِّ، أَنَّهُ قَالَ نَهَى رَسُولُ اللَّهِ صلى الله عليه وسلم عَنِ اشْتِمَالِ الصَّمَّاءِ وَأَنْ يَحْتَبِيَ الرَّجُلُ فِي ثَوْبٍ وَاحِدٍ، لَيْسَ عَلَى فَرْجِهِ مِنْهُ شَىْءٌ‏.‏