Flip (one's) lid British informal slang
React to something very strongly, as with anger, excitement, or surprise
As soon as my mom knew that I had passed the university entrance exam, she totally flipped her lid.
His parents will definitely flip their lid once they find out that their son dropped out of school.
The verb "flip" should be conjugated according to its tense.
This slang, with their allusion to losing the top of one's head, dates from the 1930s and 1940s.
This phrase emphasize that Christmas takes place once a year time, so you should grab this chance to indulge yourself and be good to others.
I've eaten a little more than usual as today is Christmas and Christmas comes but once a year, right?