This expression is used whenever something so fantastic occurs, or you receive news of such a fantastical nature, that you have to describe it with a positive adjective such as, "Fantastic" - alongside the words, "to the fourth degree." By using this expression, you are emphasizing the sheer awesomeness of whatever it is you are describing. This expression can be used when you find out you are going to be a mother/father! You can also use it when describing your last coitus session.
Person 1: So dude, how was it banging that girl we met last night??
Person 2: Dude, I have never had an orgasm of such a magnitude. It was fantastic to the fourth degree.
Person 1: Marry her.
Someone who, in relation to others, has zero parents, zero grandparents, zero great-grandparents, zero great-great-grandparents and eight great-great-great-grandparents in common.
Quadruple-4C: Person who, in relation to the other person, has zero parents, zero grandparents, zero great-grandparents, zero great-great-grandparents and eight great-great-great-grandparents in common.
My quadruple-fourth-cousin is a good person.
An event from Rebuild of Evangelion
THERE’S A FOURTH IMPACT WTF
The fourth born in a family larger than four.
I am the fourth eldest child of the Vea family.
on this day, anyone who knows zakwan must give him food. if you're rich, football boots please.
"today is may the fourth! I will give zakwan food!"