To do something “once in a blue moon” is to do it very rarely: “That company puts on a good performance only once in a blue moon. Source: theidioms.com
The blue moon is the full moon that appears a second time in the same calendar month, and this phenomenon happens only once in 32 months.
Apart from that, sometimes the full moon seems different in color, especially blue and orange, and more prominent.
You stole my smiles; it lasted for miles. You said I’ll be back soon.
But, I knew in my heart that “your soon” would only be once in a blue moon
I watched by the moon’s light, but you were never returning.
All I remember about you was my heartfelt yearnings
I faulted you
for sayings untrue
how could I have known
your life you did not own
they say you sailed away one day into a sea of blue
but the white squall was more extensive than any
strong-armed crew
our pages of life we think written in ink
doesn’t take into account that pages can sink
Once in a blue moon, you’ll find he will pull you along. Capturing your heart With his loving song
He may promise you the world with his words
But hopes are quickly dashed away with
unforeseeable swords
so your desire for that sailor to return home soon
will probably only happen once in a blue moon