When is the Sujud-as-Sawh an absolute requirement? For major variations such as adding an extra rakah, or forgetting a prostration definitely require it.
However, what if while sitting in the 2nd rakah of the total 4 rakah, you forget to get up right after shahada, and realize it only after you have partially or completely recited the Durood as well, but have not perform the Tasleem yet. Will this necessitate a sujud-as-sahw after the 4th rakah in addition to the regular sajda?
In the search for an answer, this is what I have found relevant to this, but it is not very clear. Please help clarify it, if you are able to. Jazak Allah.
What Br. KKF said. So in your example, you've messed up the order of the arkaan of the salat, which is a wajib i.e. done in the 2nd rakaat what you should have done in the 4th, so yes, you'll have to make sadja sahw for it.
There are many hadiths in support of this but I'll quote two hadith as a reference: *Book "Prayers (Salat) of Sahih Bukhari". *
Hadith No. 398
Narrated 'Abdullah: "Once the Prophet offered five Rakat in Zuhr prayer. He was asked, "Is there an increase in the prayer?" The Prophet said, "And what is it?" They said, "You have prayed five Rakat.' So he bent his legs and performed two prostrations (of Sahu).
Hadith No. 394
Narrated 'Abdullah: The Prophet prayed (and the subnarrator Ibrahim said, "I do not know whether he prayed more or less than usual"), and when he had finished the prayers he was asked, "O Allah's Apostle! Has there been any change in the prayers?" He said, "What is it?' The people said, "You have prayed so much and so much." So the Prophet bent his legs, faced the Qibla and performed two prostrations (of Sahu) and finished his prayers with Tasiim (by turning his face to right and left saying: 'As-Salamu'Alaikum-Warahmat-ullah'). When he turned his face to us he said, "If there had been anything changed in the prayer, surely I would have informed you but I am a human being like you and liable to forget like you. So if I forget remind me and if anyone of you is doubtful about his prayer, he should follow what he thinks to be correct and complete his prayer accordingly and finish it and do two prostrations (of Sahu).