Does anyone remember the chapter where Nagisa plucks off a paper from Bitch-sensei??? Behind him was this huge wavelength thing it should be before the confrontation with the God of Death, and after Bitch-sensei's teacher was introduced , I think...
No, he's speaking when he took off a sticky tag from Irina's pullover, after she started trying to change her ways in order to ensnare Karasuma. If it was before facing Noface, it was just before, then.