I bite my thumb at you
The most disrespectful way to say 'you're not cool.' It’s like throwing a banana peel at someone’s face.
I bit my thumb at my cousin during the family reunion. He bit back and it became a full-blown war.
She bit her thumb at me in the grocery line. I grabbed a loaf of bread and threw it at her.
He bit his thumb at the boss. The boss made him clean the office toilets for a week.