First Coined in the last segment of S5E3 of Key and Peele
Used when you are going to do something really cool/be the coolest person around
For instance if you were at a party, and you're going to start dancing
'Imma jump in this party fulldingle'
'Dayum, he gonna do some amazing shit up in here'
When some resigns or retires from a job, they are on "eternity leave". This can also refer to someone who has passed away, especially someone who worked somewhere for a long time, retired/resigned, then passed away later.
Oh I'm sorry, you didn't know that Kelly is on eternity leave? She resigned and moved to Hawaii!
With regrets I would like to inform you that my boss is officially on eternity leave. I will never see or hear them again. Ever.