Shama-il Tirmidhi Chapter 16, Hadith Number 4 (110).

Hazrat Ibn Umar radiyallahu anhuma reports, “When Rasoolullah sallallahu alaihe wasallam fastened an amaamah (turban), he used to put the shamlah between his shoulers (i.e. he used to put it on the back).”

Nafi says, “I had seen Abdullah bin Umar radiyallahu anhuma do it in the same manner.”

Ubaidullah, who is the student of Nafi, says, “In my time the grandson of Abu Bakr radiyallahu anhu, Qasim bin Muhammad and the grandson of Umar radiyallah anhu, Saalim bin Abdullah did the same.”

Commentary.
The practice of Sayyidina Rasoolullah sallallahu alaihe wasallam in putting the shamlah (back-end portion of the turban) varied. He usually left a shamlah on the turban. Some Ulama have gone so far as to say that he never wore a turban without a shamlah. The Muhaqqiqeen (research scholars) say that he sometimes did not leave a shamlah. When wearing a turban he observed different practices with the shamlah. He sometimes left it in front on the right shoulder; sometimes on the back between the shoulders. Sometimes the two ends of the turban were left as a shamlah. Allamah Munaawi says, “Although all methods are mentioned, the best and most correct is to leave it between the shoulders on the back.”