SKL may nakita akong post about where the word ngani originated.
So I just want to share na it came from Onhan or Ini basta Romblon dialect po siya. One of the videos na nag trending when it was first starting is from the province of Romblon. It has a different say sa ngani ng ibang bisaya. Medyo pakanta siya kasi mahaba like "nganiii". In short translation is "ngaaa". Like "Imaw nganiii" translated as "Ganun ngaaa". Exact tono talaga and the way it was said as it is now. I know this kasi I literally speak other bisaya language and iba talaga. Romblon is the only dialect who uses ngani the way people use it now.
We apply it kapag sa tingin naman paulit ulit ka, pwede din. Basta kung saan ka gagamit ng "nga" pwede mo gamitan ng "ngani". And based sa trending ngayon, tama po yong pag gamit niyo.
Kakatuwa talaga at widespread na siya.