When you eat conservatively all day and "let the dogs out" at night. I have done this for years. I picked up the term from an interesting food/ diabetes/ psych video someone (Brian maybe?) shared a link to a couple of years ago but I didn't save the link. To me it makes sense. During the day I'm busy and at night, if my BG runs low, I can run downstairs to grab a brewsky to jack it back up.