A month or so ago I referenced Sanskrit, Latin, and alluded to Hebrew culture. Here’s some French.
The term Frazz and that first grader are talking about is “esprit de l’escalier” pronounced es pree dee les kal yay. It refers to that witty reply you didn’t think of until too late. Literally “wit on the staircase”; that is, after you had left and gone upstairs. Ah, those French.