If and only if my parents should happen to read this, I'm potentially about to dox myself to them alone.
Anyway, in some family photo album I'm quite certain still exists, there's a picture of me from when I was ~3–4 years old, and had fallen asleep while the three of us were out on our boat. If you know what the seats on a boat like the one we had look like, you know they're fairly low. Well I had fallen asleep standing up, right in front of one of those seats. I was still standing up in the picture; the only difference was that my entire upper body was on the seat.
Literally, legs still completely vertical, torso completely horizontal. I wish I could still sleep that easily, honestly.