Faaff - A lazy way to tell someone to leave you alone. It works best

A lazy way to tell someone to leave you alone. It works best when you say it really fast and pretend you're talking to someone else.

I said 'Faaff' to my mom when she tried to give me a third slice of pizza.

I said 'Faaff' to my crush when he kept texting me during class.

I said 'Faaff' to my dog when he ate my homework.