Just noticed this tag and I'm sure I'll find it useful as I thought that mouth shape needed a specific tag. I had been tagging those as :< open_mouth but that doesn't even come close to giving the results I'd want (given the open triangular mouths and group images with multiple expressions). I was going to change the mention of a "teardrop shape" from the :< wiki (which to me, is the same thing as chestnut_mouth: a pointed top but rounded bottom) to note this tag. I think it should stand as a separate tag and not be implicated, but that's arguable, so I'm bringing it up for discussion before making any wiki changes.
Updated by jxh2154