(20) باب اشْتِمَالِ الصَّمَّاءِ
Narrated Abu Sa`id Al-Khudri:
Allah's Messenger (ﷺ) forbade two ways of wearing clothes and two kinds of dealings. (A) He forbade the dealings of the Mulamasa and the Munabadha. In the Mulamasa transaction the buyer just touches the garment he wants to buy at night or by daytime, and that touch would oblige him to buy it. In the Munabadha, one man throws his garment at another and the latter throws his at the former and the barter is complete and valid without examining the two objects or being satisfied with them (B) The two ways of wearing clothes were Ishtimal-as-Samma, i e., to cover one's shoulder with one's garment and leave the other bare: and the other way was to wrap oneself with a garment while one was sitting in such a way that nothing of that garment would cover one's private part.
Reference: Sahih al-Bukhari 5820
In-book reference: Book 77, Hadith 37
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 7, Book 72, Hadith 710