So, I think I've discovered something, but you guys might already know about this.
I was on vacation, so I didn't really have time to take care of my V4, so when she lost happy hearts I would usually just feed her a snack instead of play a game with her, like I usually do.
Because of this I got her weight up to 60. I think I noticed before that she never did that falling motion, where a tamagotchi falls on their face XD
But since her weight was at 60, she started doing it. When I got home, I played a whole bunch of games with her and got her weight to about 48-50, and I observed her motions for a couple of minutes. She stopped falling.
Does anyone know if a tamagotchi's weight is what causes them to fall (or not fall)?