The World Federation One Stop Fiqh

Ruling 1183

If in a nāfilah prayer one does something that would make it obligatory for him to perform sajdatā al‐sahw were he to do that thing in an obligatory prayer, or if he forgets to perform one sajdah, then it is not necessary for him to perform sajdatā al‐sahw or to perform a qaḍāʾ sajdah after the prayer.