When you go for a shit in the toilet and there's no seat or you don't wont to sit on it, you pull your pants down and assume the position a down hill skier would use.
Bloke 1 "There's no seat in the toilet"
Bloke 2 "Best go shit skiing then!"
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.