Is it normal that my teeth are usually slightly open?

My tongue usually dangles outside my mouth and my eyes point outward

Are you aware of the term "mouth-breather"?

It's not a great look.

I have no idea if it's common, but that's how I normally hold my jaw as well: teeth slightly separated and tip of tongue against the gums just above my incisors.

You do occasionally see people (most often men) with muscles twitching under their cheeks, and that has to mean their teeth are clenched. I think that's not a good look either, since it suggests someone who's on-edge, and it would probably result in damage to teeth in the long-term as well as aching jaw and neck muscles.

I've never really thought about it until now, but I think I do it as well, so I think it's probably normal!