the acronym MASAPER (pronounced Mass-APP-er) stands for "Minimize As Soon As Parent Enters Room". Therefore the Masaper Reflex is the reflex action of minimizing whatever's on your computer screen, as quickly as possible, before one of your parents can see it. individuals between the ages of 13 and 19 tend to have the best Masaper Reflex.
A: man, we're so lucky Mum didn't catch us on 4chan yesterday! she would have killed us if she'd seen what we were looking at!
B: Yeah. Your Masaper Reflex really saved our asses!