I bite my thumb at thou! - It means you’re ready to punch someone. Like a middle school

It means you’re ready to punch someone. Like a middle schooler who just got called a nerd and is thinking about a lunch fight.

I bite my thumb at thou! #MiddleSchoolRage

I’m not even mad. I’m just biting my thumb at thou. #CoolDude

You called me a faggot. I bite my thumb at thou! #BathroomFight