Sujud-ul-Sahw before or after Taslim?

Q 1: Should the Sujud-ul-Sahw (Prostration of Forgetfulness) be offered before or after the Taslim (salutation of peace ending the Prayer) when missing or doing extra Rak`ah (unit of prayer) in Salah (prayer)? Likewise, what if other actions are done excessively?

A: Sujud-ul-Sahw is obligatory in all situations of forgetfulness that would otherwise nullify a Salah if committed intentionally. It is offered before saying the Taslim according to the Hadith related by Abu Sa`id, `Abdullah ibn Buhaynah and others. However, if Sujud-ul-Sahw is performed due to missing one or more Rak`ahs or an inadvertent action that the person had probably done, then it should be performed after the Taslim. The Hadith related by Abu Hurayrah and `Imran ibn Husayn about the story of Dhul-Yadayn support this and the Hadith narrated by Ibn Mas`ud shows that if there is doubt in a Salah, it should be offered based on what is certain.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.