Sunan an-Nasa'i 1262
سنن النسائي#1262SahihIt was narrated that Abu Humaid As-Sa'idi said:"At the end of the last two rak'ahs of the prayer, the Prophet (ﷺ) would move his left foot forward and sit on his left buttock, Mutawarrikan, then he would say the taslim
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Abu GhuddahSahih
Al-AlbaniSahih
Zubair Ali ZaiIsnaad Sahih
In-book reference: 13:84