underwear 95% of the time
during my junior and senior years of highschool i usually crashed at any 1 of 3 certain friends' houses and i'd just sleep on their couches fully clothed with no blankets. got used to that so i still do it out of habit sometimes in my own bed if i get home after midnight or im just straight exhausted
i have like 10 pairs of pj/sweat pants that i've gotten over the years as xmas/bday presents, but i rarely wear them. also sleeping under sheets with a shirt on is impossible for me