purple moon
Special name given to the blue moon of April, following the pink moon early in the same month.
Purple moon is extremely rare. You've got to see it! That only happens once in a purple moon.
once in a purple moon
An extremely rare occurrence, rarer than 'once in a blue moon'.
A particular team winning the championship happens once in a purple moon. A total solar eclipse seen from Europe happens once in a purple moon.
purple helmet moon man
slang for penis
i want to send my purple helmet moon man on a cave diving exploration in your vag.