It it used to some up the feelings of when you have met someone online and have yet to meet them in person. Where you are either in love/lust/flattered, eager to meet them - all from only online interaction
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.
We have a Zoom meeting in a few minutes and I’ll probably go pajama casual.