"School flashbacks" refers to unexpectedly remembering past experiences or moments from one's time in school. It can evoke strong memories or emotions associated with those specific periods in a person's life. Full definition
I keep having high school flashbacks of flares + rain = soggy pants. (classicingray.com)
I considered paper - macheing my own for about a second, but elementary school flashbacks of nauseating glue and globs of wet newspaper haunted me. (homestoriesatoz.com)
Principal photography for the film commenced just recently, and with Zoolander 2 on deck this year as well, I'm beginning to have high school flashbacks of spilling my popcorn at my multiplex from laughing so hard. (waytooindie.com)