https://hinative.com/questions/20311413
https://www.quora.com/English-speakers-what-does-Ill-sink-my-teeth-in-disbelief-mean-Its-from-Dua-Lipas-song

Как говорят, "It doesn't mean anything." - типично для современной "лирики".
Скорее всего, это должно обозначать "стиснуть зубы в неверии".
Есть идиома "to sink one's teeth INTO something" - значение другое.

This is "musical English" and it's not idiomatic nor does it make any sense outside of the context of the song. It WANTS to mean that she embraces the emotions of shock and disbelief she feels upon having found someone new, but only "musically." This doesn't work in the real word, and outside of this song, would leave any native speaker scratching their heads — first and foremost because we normally sink our teeth INTO something delicious [actual] or intriguing [figurative]. If I were you, Ksenia, I'd take this line at face value and not let it influence my English at all. We don't talk like this.

Окунулась в неверие?