A day of celebration of one's birth. Invented by a child, used by adults because it is just better to be birfed than birthed.
Because, it's your birfday and you can say it anyway you want too.
Yo' Happy Birfday, man.
Go girl, it's your Birfday!
Pajama casual is a term used when working from home and preparing for a video conference. All business above the waist and your pajama pants down below.