When an Anime girl has a small, white fang that shows off whenever she smiles or yells. Kawaii Fang usally appears on tsudere waifus and lolis. Girls like Natsuki from Doki Doki .Literture Club have a Kawaii Fang
Natsuki's Kawaii Fang is super adorable! This is why she's my waifu
When an Anime girl, usally a tsundere show off a small fang when she talks/smile, that for some reason is considered to be cute. Also, usally it's the only type of teeth you will see on Anime girls.
Sensible person: "WTF, why does that girl has only one fang in her mouth?! Where is the rest of the teeth?
Weeabo: "it's called Kawaii Fang and it's cute!"
"Sensible person: "what