the definition itself was actually created by a lost and now famous video of one guy and two girls putting a funnel in one girl's ass and pouring milk into it. the other girl then uses a straw and drinks the milk out of the other girl's ass. this video was around during the mid to late 90s and has since been lost. a lucky few may still have this video in their archive.
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.