Is the one who experiences obsessive doubts in prayer subject to the prostration of forgetfulness (sujood al-sahw)? And what is its manner (before or after the salaam)? And is there a tashahhud for it?

If a person experiences excessive doubt in prayer to the point where it becomes a [waswas] (obsessive whisper), then the prescribed action for them is to disregard this [waswas] and pay no attention to it. In such a case, the prostration of forgetfulness (sujud al-sahw) is not prescribed for them.

As for the normal prostration of forgetfulness, if it is due to a deficiency (naqs), its place is before the salutation (taslim). If it is due to an addition (ziyadah), its place is after the salutation.

The tashahhud (testification of faith) is not prescribed after the prostration of forgetfulness. Rather, the worshiper should pronounce the salutation immediately after completing the two prostrations. Nothing authentic has been reported in this regard from the Prophet, peace and blessings be upon him. The hadith that mentions the tashahhud after the prostration of forgetfulness is weak and irregular (shadh).