A bliss ninny noun phrase
Used to describe someone who is extremely happy
She was a bliss ninny when hearing that she passed the exam.
To make someone feel more confident or happy, especially when they thought that they can't achieve what they want
Happy or cheerful; in a good mood
To smile broadly
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?