ثُمَّ يَرْفَعُ رَأْسَهُ، وَيُكَبِّرُ، وَإِذَا اطْمَأَنَّ جَالِسًا كَبَّرَ وَسَجَدَ. فَإِذَا اطْمَأَنَّ سَاجِدًا كَبَّرَ، وَاسْتَوَى قَائِمًا عَلَى صُدُورِ قَدَمَيْهِ، وَلَا يَقْعُدُ، وَلَا يَعْتَمِدُ بِيَدَيْهِ عَلَى الْأَرْضِ.
Meaning: Raise the head and say takbir; once settled sitting, say takbir and make the second prostration. After settling in that prostration, say takbir and rise upright on the fronts of the feet, without an intermediate sitting or leaning on the hands.
The wording explicitly mentions composure while sitting and while in the second prostration.