When I'm wearing pajama pants... and I usually sleep naked.
I had some weird kind of anti-underwear feeling during childhood. I would never want to buy new underwear, like never never. Don't have that anymore, now underwear is actually part of a fetish I have. They used to see it as a sign of autism, but I'm over that phase.
Sometimes when I walk my dog I only use sweatshorts and when it's summer, I usually sleep naked so if I wake up and have to go somewhere in the house I usually just put the pijama pant on before going back to bed.