Hadithcore
Hadith #2104190

And in the narration of Muslim:

'the Prophet (ﷺ) performed two Sajdatus-Sabw after Taslim and talking'.

وَلِمُسْلِمٍ : { أَنَّ اَلنَّبِيَّ ‏- صلى الله عليه وسلم ‏-سَجَدَ سَجْدَتَيْ اَلسَّهْوِ بَعْدَ اَلسَّلَامِ وَالْكَلَامِ } [1]‏

References2 variants
Sunnah.com reference
Book 2, Hadith 236
Arabic/English book reference
Book 2, Hadith 0