Sujud Sahwi

Sujud Sahwi or Sajdah of forgetfulness occurs during the ritual salat prayer.

In either cases the person corrects his/her salat by doing the Sujud Sahwi.

Prophet Muhammad has detailed in the hadith what must be done in the case of a worshipper adding or subtracting something from their salat due to forgetfulness.

[1] Before making the tasleem (i.e. saying as-Salaam ‘Alaikum on both sides) the person must say the takbir (i.e. Allāhu Akbar) while sitting and then make two prostrations as per normal sujud.

Taharr is when one has doubt as to whether they added or subtracted from their prayer, but then realise what they did wrong.