I suggest that we never do grammar pop ups during stories. The unconscious focus on the language gets interrupted when we do that.
We don’t need hand comprehension checks either. Search that term for an article on that. We do need “What did I just say” comprehension checks.
Doing pop up grammar interrupts the unconscious process of focusing on the message, watching a movie in their minds. So I suggest that we only do pop ups during reading classes, not during the story creation part of class.