Liaison office of Grand Ayatullah Sayyid Ali Al Sistani (L.M.H.L) in London, Europe, North and South America.
Ruling 1236. The method of performing sajdatā al-sahw is that immediately after the salām of the prayer, one must make the intention of sajdatā al-sahw and place his forehead, based on obligatory precaution, on something on which performing sajdah is permitted. The recommended precaution is that one should say dhikr in the sajdah, and it is better that he say:
بِسْمِ اللهِ وَبِاللهِ، السَّلَامُ عَلَيْكَ أَيُّهَا النَّبِيُّ وَرَحْمَةُ اللهِ وَبَرَكَاتُهُ
bismil lāhi wa billāhi, assalāmu ʿalayka ayyuhan nabiyyu wa raḥmatul lāhi wa barakātuh
In the name of Allah and by Allah. Peace be upon you O Prophet, and Allah’s mercy and His blessings (be upon you too).
Then, he must sit up and go into sajdah again, and he should say the dhikr mentioned above. [He must then sit] and say tashahhud, after which he must say:
السَّلَامُ عَلَيْكُمْ
assalāmu ʿalaykum
Peace be upon you all.
And it is preferable that he adds the words:
وَرَحْمَةُ اللهِ وَبَرَكَاتُهُ
wa raḥmatul lāhi wa barakātuh
And Allah’s mercy and His blessings (be upon you too).